
Copyright N" 



COPYRrOHT DEPOSIT. 




DR ROBERT KOCH WHO DISCOVERED THE CAUSE OF TUBERCULOSIS 



BOVINE TUBERCULOSIS 

AND 

ITS CONTROL 



BY 
VERANUS ALVA MOORE, B.S., M.D., V.M.D. 

Professor of Comparative Pathology, Bacteriology and Meat Inspection, 

New York State Veterinary College at Cornell University, 

and Director of the College 



THIRTY FULL PAGE ILLUSTRATIONS 



ITHACA, N. Y. 

CARPENTER CSl. COMPANY 

1913 



SF80& 

.tiT5 



COPYRIGHT 1913 

BY 

CARPENTER & COMPANY 



©Ci.A343916 



TO THOSE WHO ARE ACTIVELY 
INTERESTED IN THE ERADICATION 
OF BOVINE TUBERCULOSIS THIS 
VOLUME IS DEDICATED. 



PREFACE 

THE early belief that the bacteria of human and of bovine 
tuberculosis were identical and that large numbers of 
people became infected from diseased cattle caused bovine 
tuberculosis to stand out somewhat conspicuously among 
the affections of animals. 

The sanitary significance of this affection in addition to 
its great economic importance have caused it to be very care- 
fully studied in each and all of its phases. Although there 
is still much to be ascertained concerning it, knowledge of 
this disease has become quite definite in many respects. How- 
ever, it is a complicated subject with many difficult questions 
still to be answered. These relate to the various diagnostic 
tests and the differentiation of its cause from closely allied 
species of bacteria. 

The preparation of this volume was undertaken largely 
at the instance of practitioners of veterinary medicine and 
health officers who during recent years have sought for a 
summary of the knowledge of bovine tuberculosis and its 
control. It seemed that for those who are intelligently work- 
ing to eradicate this scourge benefit would be derived from 
bringing together the results of the more important investi- 
gations on the nature, diagnosis and various methods for the 
control of this disease. 

Individuals, commissions, government laboratory workers 
and state experiment stations have made many contribu- 
tions to the knowledge of this subject. While it is impossible 
to summarize this literature, the publications listed and the 
citations given will, it is believed, make it possible for those 
interested in the subject to ascertain fully the details of the 
work that has been done on this disease. 

I am indebted to Dr. S. H. Burnett of this laboratory 
and Dr. A. R. Keith for the photographs from which the 
illustrations were made. The original specimens are in the 
collection of the Department of Comparative Pathology and 
Bacteriology of the New York State Veterinary College. 

V. A. M. 

Ithaca, N. Y., January, 1913. 



TABLE OF CONTENTS 

List of Illustrations vi 

References vii 

Page 
CHAPTER I. 

History of Tuberculosis in Cattle 1 

CHAPTER n. 
Distribution, Economic and Sanitary Importance of Bovine Tuber- 
culosis 5 

CHAPTER III. 
The Cause of Tuberculosis in Cattle 14 

CHAPTER IV. 

The Nature of Tuberculosis and the Changes Produced in the Tissues 

by Tubercle Bacteria 22 

CHAPTER V. 
Symptoms of Tuberculosis in Cattle 29 

CHAPTER VI. 
Methods of Dissemination 33 

CHAPTER VII. 
The Diagnosis of Tuberculosis in Cattle 51 

CHAPTER VIII. 
Tuberculin and Its Use 55 

CHAPTER IX. 

Physical Examination in Detecting Tuberculosis in Cattle 72 

CHAPTER X. 
Immunization of Cattle Against Tuberculosis 76 

CHAPTER XI. 
The Control of Bovine Tuberculosis 85 

APPENDIX. 
Report of the International Commission on the Control of Bovine 

Tuberculosis 105 



ILLUSTRATIONS 



I. Tubercle bacteria. 

II. Cultures of tubercle bacteria. 

III. Growth of tubercle bacteria on glycerin bouillon. 

IV. Structure of a tubercle. 

V. Temperature curves after tuberculin. 

VI. Bronchial glands (Smith). 

VII. Tuberculous lung. 

VIII. Tubercle opening into a bronchus. 

IX. Tuberculous lung, diaphragm and liver. 

X. Tuberculous nodules on lung. 

XI. Tuberculous pleura. 

XII. A cross section of a tuberculous heart. 

XIII. Tuberculous gland. 

XIV. Tuberculous gland. 

XV. Tuberculous glands. 

XVI. Tuberculous mediastinal gland. 

XVII. Enlarged tuberculous mesenteric glands. 

XVIII. Tuberculous ulcers in the intestine. 

XIX. Tuberculous ulcers and enlarged glands at ileo-caecal valve. 

XX. Tuberculous liver. 

XXI. A section of tuberculous liver. 

XXII. A tuberculous omentum. 

XXII I. A tuberculous omentum. 

XXIV. A tuberculous omentum. 

XXV. A tuberculous spleen. 

XXVI. A tuberculous udder. 

XXVII. Tuberculous lesions in skin. 

XXVIII. A tuberculous uterus. 

XXIX. A tuberculous focus in bone. 

XXX. A tuberculous spleen from a pig. 



REFERENCES 

The following are a few of the more available publications on bovine 
tuberculosis. The reports of State and Government Departments of Agri- 
culture and many boards of health as well as the veterinary and medical 
literature of the last twenty years contain many articles on this subject. 

Curtice. The detection of tuberculosis in cattle. Annual Report, Bureau 

of Animal Industry, U. S. Dept. of Agric, 1895-96. 
Dorset. Experiments concerning tubercvilosis. Bulletin 52, Bureau of 

Animal Industry, 1904. 
JOHNE. Geschichte der Tuberkulose. Leipsic. 1883. 
Koch. The etiology of tuberculosis. Mitt, aus dem. Kaiseri. Gesund- 

heitsamte, Bd. II (1884). Translated in Vol. CXV, New Sydenham 

Society. 
Koch. The combating of tuberculosis in the light of the experience that 

has been gained in the successful combating of other infectious diseases. 

Amer. Vet. Review, Vol. XXV (1901), p. 441. 
MoHLER. Infectiveness of milk of cows which have reacted to the tuber- 
culin test. BuUedn 44, Bureau of Animal Industry, 1903. 
MOHLER. The tuberculin test of cattle for tuberculosis. Farmers' Bulletin 

351, U. S. Dept. of Agric, 1909. 
MoHLER AND WASHBURN. A Comparative study of tubercle bacilli from 

varied sources. Bulletin 96, Bureau of Animal Industry, 1907. 
Moore. A report on bovine tuberculosis. N. Y. State Dept. of Agric, 1903. 
NocARD. The animal tuberculosis. New York. 
Pearson. The Pennsylvania plan for controlling tuberculosis of cattle. 

Proceedings Amer. Vet. Med. Assn., 1899, p. 161. 
Pearson. Tuberculosis in cattle and the Pennsylvania plan of its repression. 

Bulletin 75, Penn. Dept. of Agric, 1901. 
Pearson. The repression of tuberculosis in cattle by sanitation. Bulletin 

74, Penn. Dept. of Agric, 1901. 
Peterson. The elimination of tubercle bacilli from man and animals. 

Thesis for Doctor of Philosophy, Cornell University. 1910. 
Reports of the International Congress on Tuberculosis, especially Sixth 

Congress held in Washington, D. C, 1908. 
Report of the Royal Commission on Tuberculosis (Human and Animal). 

London. 1907. 



vUi REFERENCES 

Report of the International Commission on the Control of Bovine Tuber- 
culosis appointed by the American Veterinary Medical Association, 
1910. Also published as Circular 175 of the Bureau of Animal Industry, 
U. S. Dept. of Agric, 1911. Reprinted in Appendix. Also Farmer's 
Bulletin No. 473, U. S. Dept. Agric, 1911. 

Salmon. Legislation with reference to bovine tuberculosis. Bulletin 28, 
Bureau of Animal Industry, 1901. 

Salmon. The tuberculin test of imported cattle. Bulletin 32, Bureau of 
Animal Industry, 1901. 

Salmon. Tuberculosis of the food-producing animals. Bulletin 38, Bureau 
of Animal Industry, 1906. 

SCHROEDER. Milk and its products as carriers of tuberculosis infection. 
Circular 143, Bureau of Animal Industry, 1909. 

ScHROEDER AND CoTTON. The relation of tuberculous lesions to the mode 
of infection. Bulletin 93, Bureau of Animal Industry, 1906. 

ScHROEDER AND COTTON. Experiments with milk artificially infected with 
tubercle bacilli. Bulletin 86, Bureau of Animal Industry, 1906. 

SCHROEDER AND COTTON. Tubercle bacilli in butter. Circular 127, Bureau 
of Animal Industry, 1908. 

SCHROEDER AND MOHLER. The tuberculin test of hogs. Bulletin 88, Bu- 
reau of Animal Industry, 1906. 

Shumway. a hand-book on tuberculosis among cattle, 1895. 

Smith. Investigations concerning bovine tuberculosis with special reference 
to diagnosis and prevention. (Pathological part.) Bulletin No. 7, 
Bureau of Animal Industry, 1894. 

Ward and Baker. Experiments with the intradermal test for tuberculosis 
in cattle. Proceedings Am. Vet. Med. Assn., 1910. 

Bulletins on Tuberculosis from the Various State 
Agricultural Experiment Stations 

Bang. The application of tuberculin in the suppression of bovine tuber- 
culosis. Bulletin 41. Massachusetts. 1896. (A translation.) 

Beach. The history of a tuberculous herd of cows. Bulletin 24. Storrs, 
Conn. 1902. 

Bitting. Bovine tuberculosis in Indiana. Bulletin 63. Indiana. 1896. 

Brewer. Tuberculosis. Bulletin 41. Utah. 1895. 

Briscoe and MacNeal. Tuberculosis of farm animals. Bulletin 149. 
Illinois. 1911. 

Buckley, Tuberculosis of animals. Bulletin 145. Maryland. 1910. 



REFERENCES ix 

Cary. Bovine tuberculosis. Bulletin 67. Alabama. 1895. 

Conn. The relation of bovine tuberculosis to that of man and its signifi- 
cance in the dairy herd. Bulletin 23. Storrs, Conn. 1902. 

DiNWiDDlE. The relation of virulence for the domestic animals of human 
and bovine tuberculosis. Bulletin 57. Kansas. 1899. 

DiNWiDDiE. The relative susceptibility of the domestic animals to the 
contagia of human and bovine tuberculosis. Bulletin 63. Kansas. 1900. 

Fischer. Bovine tuberculosis. Bulletin 69. Kansas. 1898. 

Glover. Relation of bovine to human tuberculosis. Bulletin 66. Colorado. 
1901. 

Grange. Tuberculosis. Bulletin 133. Michigan. 1896. 

Harding, Smith and Moore. The Bang method, etc. Bulletin 277. Ge- 
neva, N. Y. 1906. 

Hills and Rich. Bovine tuberculosis. Bulletin 42. Vermont. 1894. 

Law. Tuberculosis in relation to animal industry and public health. Bulle- 
tin 65. (Cornell), New York. 1894. 

Law. Experiments with tuberculin on non-tuberculous cows. Bulletin 81. 
(Cornell), New York, 1894. 

Law. Tuberculosis in cattle and its control. Bulletin 150. (Cornell), 
New York. 1898. 

Marshall. A study of normal temperatures and the tuberculin test. Bulle- 
tin 159. Michigan. 1898. 

Marshall. Killing the tubercle bacilU in milk. Bulletin 173. Michigan. 
1899. 

Mayo. Some diseases of cattle, Texas itch, blackleg, tuberculosis, Texas 
fever. Bulletin 69. Kansas. 1897. 

Mayo and Kerr. Treatment of bovine tuberculosis. Bulletin 199. Vir- 
ginia. 1912. 

Moore. Bovine tuberculosis. Bulletins 225 (1904) and 250 (1908). (Cor- 
nell), New York. 

Moore. The elimination of tubercle bacteria from infected cattle, and the 
control of bovine tuberculosis and infected milk. Bulletin 299. (Cornell) , 
New York. 1911. 

Nelson. On the use of Koch's lymph in the diagnosis of tuberculosis. Re- 
port of the biologist. New Jersey. 1893. 

Nelson. Experimental studies of the Koch test for tuberculosis. New 
Jersey. 1895. 

Nelson. The suppression and prevention of tuberculosis of cattle and its 
relation to human consumption. Bulletin 118. New Jersey. 1896. 



X REFERENCES 

Nesom. Tuberculosis of cattle. Bulletin 50. South Carolina. 1900. 

Paige. History of tuberculosis in a college herd. Use of tuberculin in diag- 
nosis. Bulletin 26. Massachusetts. 1894. 

Pearson. Tuberculosis of cattle. Bulletin 29. Pennsylvania. 1894. 

Reynolds. Bovine tuberculosis. Bulletin 51. Minnesota. 1896. 

Reynolds and Beebe. Dissemination of tuberculosis by the manure of 
infected cattle. Bulletin 103. Minnesota. 

Russell. Tuberculosis and the tuberculin test. Bulletin 40. Wisconsin. 
1894. 

Russell. The history of a tuberculous herd of cows. Bulletin 78. Wis- 
consin. 1899. 

Russell. A lesson in bovine tuberculosis. Bulletin 114. Wisconsin. 1904. 

Russell. Two ways of treating tuberculosis in herds. Bulletin 136. Wis- 
consin. 1905. 

Russell. The spread of tuberculosis through factory skim milk with sug- 
gestions as to its control. Bvdletin 143. Wisconsin. 1907. 

Russell and Hastings. Bovine tuberculosis in Wisconsin. Bulletin 84. 
Wisconsin. 1901. 

Russell and Hastings. Distribution of tuberculosis in suspected and non- 
suspected herds in Wisconsin. Bulletin 133. Wisconsin. 1906. 

Russell and Hastings. Tuberculin test and its manner of application. 
Bulletin 134. Wisconsin. 1906. 

Russell and Hastings. A catechism on bovine tuberculosis. Wisconsin. 
1911. 

Russell and Hoffmann. A 3-year campaign against bovine tuberculosis 
in Wisconsin. Bulletin 175. Wisconsin. 1909. 

Stalker and Niles. Investigation of bovine tuberculosis with special refer- 
ence to its existence in Iowa. Bulletin 108. Iowa. 1895. 

Stance. Tuberculosis and its detection. Bulletin 107. Iowa. 1912. 

Thorne. Bovine tuberculosis. Bulletin 108. Ohio. 1899. 

Van Es. Bovine tuber cvilosis. Bulletin 77. North Dakota. 1907. 

Ward and Haring. Bovine tuberculosis. Bulletin 99. California. 1908. 

Williamson and Emery. Tuberculosis and its prevention. Bulletin 117. 
North Carolina. 1895. 




CHAPTER I 

History of Tuberculosis in Cattle 

UBERCULOSIS is one of the oldest diseases 
of cattle of which we have identifying records. 
The Mosaic laws (Leviticus xxii, 22) contain 
rules that the flesh of animals which sufifer 
from "wen or scurvy" should not be used as 
food. The Talmud, especially the Mishnah, 
codified at the close of the second century, and the Gemara 
(fifth century) contain numerous enactments against the eating 
of such flesh. It is stated on good authority that "kandi" 
and "timari" refer to tuberculosis. It is evident that in the 
eleventh and twelfth centuries, tuberculosis was fairly well 
known to the Arabian Rabbi, Isaak ben Jacob Alfasi, an 
authority on the Talmud, and the French physician Rashi 
(1040-1105). 

In the ninth century, the Franks enacted ecclesiastical 
laws against the eating of the flesh of cattle and swine which 
were affected with tuberculosis of the serous membranes. In 
1370 it was forbidden in Munich to offer for sale the flesh of 
tuberculous animals. Similar laws were passed in 1343 in 
Wiirtsburg; in 1394 in Passau; in 1401 in Landshut; in 1558 
in Wiirtemburg; and later similar regulations were enforced 
in other provinces. 

In 1702 Florinus gave a description of the symptoms of 
the disease during life. At that time the name "French 
disease" was applied to it in Germany. This grew out of the 
belief which prevailed in certain quarters that tuberculosis 
was connected with or related to human syphilis. The term 
Franzosenkrankheit is said to have been first used by Helmont. 
In consequence of this theory of its origin, all tuberculous 
cattle had to be destroyed. Severe penalties were imposed 
for the violation of this sanitary law. 



2 BOVINE TUBERCULOSIS 

In 1783, the Berlin Board of Health published regulations 
for meat inspection in which the characteristics of the "French 
disease" were described; rejected the theory that tubercu- 
losis was related to syphilis; and made the declaration that 
the flesh of tuberculous cattle was fit for human food. In 
the same year, Kersting of Hanover expressed a similar view 
in a report to the Government of Mecklenburg- Strelitz. 
Franck of Baden expressed the opinion that the consumption 
of the flesh of cattle which were only slightly affected with 
tuberculosis might be permitted. Graumann declared in 
1784, in a government order of Mecklenburg- Schwerin, that 
such meat might be eaten. Following this declaration and 
perhaps in consequence of it, all the orders throughout Prussia 
which had been issued against the consumption of the flesh 
of tuberculous cattle were cancelled in 1785, and throughout 
Austria in 1788. 

In 1816, Tscheulin laid down certain rules with regard to 
the inspection of meat from tuberculous cattle in which three 
stages or degrees in the extent of the disease of bovine tuber- 
culosis were recognized, namely: (1) that in which only the 
tubercles were to be removed; (2) that in which the diseased 
parts were to be destroyed and the balance of the meat to 
be sold at a cheap price; and (3) carcasses which were declared 
to be entirely unfit for food owing to the extent of the disease. 
A similar procedure regarding meat inspection was carried out 
in Southern Germany, Switzerland, Austria, France, Belgium, 
Spain, Italy and other countries. 

Consumption and bovine tuberculosis were for many 
years considered as two different diseases. Thus Virchow, 
Schiippel, and others declared that the tubercles in cattle were 
lymphosarcomata. Leisering regarded them as sarcomata. 
On the other hand, Spinola and Haubner maintained that 
bovine tuberculosis and human tuberculosis were identical. 

Klencke* published a work in 1846 in which he accuses 

*Klencke. Ueber Aussteckung u. Verbreitung der Scrophelkrankheit 
bei Menschen durch den Genuss der Kuhmilch. Leipzig, 1846. 



HISTORY OF TUBERCULOSIS IN CATTLE 3 

cow's milk of being the cause of a certain sickness in children. 
He maintained that there is a positive connection between the 
milk of scrofulous and tuberculous cows and the frequent 
development of scrofula (tuberculosis of the glands of the 
neck) in bottle-fed children. His observations seem to be the 
first recorded concerning the direct communicability of tuber- 
culosis. In 1865, tuberculosis was demonstrated to be infec- 
tious. In that year, Villemin showed that it could be pro- 
duced in healthy animals by inoculating them with pieces of 
tuberculous tissue. His results were confirmed by a number 
of other investigators. Thus Chauveau, in 1868, produced 
tuberculosis experimentally by feeding tuberculous material 
to cows. These experiments were confirmed by Klebs, Cohn- 
heim and Gerlach. The last mentioned was the first to show 
that tuberculosis could be produced by feeding animals the 
flesh and milk of tuberculous cattle. As a result of these 
experiments, attempts were at once made to prevent the sale 
of the flesh of tuberculous animals. Since the previous regu- 
lations respecting the sale of tuberculous meat had already 
been abrogated, or were in force in but a few places, these 
attempts were met by the vigorous opposition of those finan- 
cially interested. 

There was, perhaps, a tendency at that time for hygienists 
to take an extreme position as to the danger of using the pro- 
ducts of tuberculous animals. For instance, Gerlach said: 
"Pearl disease is not only incurable but it renders the animal 
completely worthless; meat and milk from such animals are 
never to be used as human food in a raw or imperfectly cooked 
condition." 

It must be remembered in this connection that the early 
stages of tuberculosis as now recognized were then almost 
unknown, for a cow that was then considered to be tuber- 
culous was in a rather advanced stage of disease. As earlier 
stages of the disease were recognized, the German veterinary 
council took a more conservative position and in 1875 rendered 
an opinion to the effect that experience and observation did 



4 BOVINE TUBERCULOSIS 

not justify the extreme measures that were advocated by 
many, and the Imperial authorities were asked to furnish 
means for the study of the question as to whether, and to 
what extent, the use of the flesh and milk of tuberculous 
cattle could be injurious to people. The results of this further 
study have brought about the development of rigid systems 
of meat inspection. The United States stands foremost in 
the efficiency of this service. 

In 1882, Robert Koch discovered the bacterium (bacillus) 
of tuberculosis and thus completed the already abundant 
evidence that tuberculosis was a specific, infectious disease. 
The finding of its specific cause led to many careful and ex- 
tended investigations into its nature, the means by which it 
is spread, and the measures that must be adopted if its spread 
is to be checked. 

The discovery of tuberculin by Robert Koch in 1890 
marked the beginning of widespread efforts to eradicate 
bovine tuberculosis. The later discovery by Theobald Smith 
that bovine and human tubercle bacteria were not identical 
in their morphology, cultural characters and virulence precipi- 
tated one of the most intense scientific investigations that 
modern medicine has witnessed. It has been participated in 
by a very large number of sanitarians, bacteriologists and 
pathologists in many countries. The results of these numerous 
inquiries have given us very definite knowledge of the nature 
of the disease which, if properly applied, will, it is believed, 
enable cattle owners to eliminate tuberculosis from their 
herds, if it is there, and to keep it out, if it is not present. 



CHAPTER II 

Distribution, Economic and Sanitary Importance 
OF Bovine Tuberculosis 

At the present time, tuberculosis is a wide-spread disease 
among cattle. It is reported to be more or less prevalent in 
nearly every locality where dairying is an active industry. It 
is also found in range cattle where it has been introduced with 
breeding stock. Ward states that 10 per cent of the cattle 
killed in the South San Francisco stock yards that came from 
the open ranges were tuberculous. In those parts of the 
country where the dairy industry is restricted to small herds 
and where there has been very little exchange of cattle it is 
rare. On the other hand, where milk production is the chief 
occupation of the people and where the supply of milk is 
continuous throughout the year, tuberculosis among cattle 
is very common. Thus we find the spread of this disease 
greatly aided by the habits of dairymen that were adopted 
to meet the demands of the cities for fresh milk. Dr. Melvin, 
Chief of the Bureau of Animal Industry, states that it is 
estimated that about 10 per cent of the dairy cattle of the 
country are infected. 

In tracing the spread of tuberculosis it is found that it 
was introduced into certain localities of Western Europe and 
into America, from which centers it spread somewhat slowly 
at first but gradually increased with the development of the 
cattle traffic. From the infected localities it extended to 
uninfected ones through the introduction of one or more 
diseased animals. The cattle of Denmark, according to Prof. 
Bang, became infected from those imported from Scotland. 
The United States and Canada introduced tuberculosis in 
a similar manner although it is not known from what country 
or at just what time it occurred. 

The early history of tuberculosis in cattle in the United 



6 BOVINE TUBERCULOSIS 

States and Canada is very obscure. A careful search in the 
papers, magazines and published reports of Agricultural Soci- 
eties and organizations as well as the veterinary literature fails 
to reveal evidence of the time of its first introduction into 
this country. In the American Farmer for 1822 (p. 152), Dr. 
Eli S. Davis of Abberville, S. C, concludes that the theory 
of the contagiousness of tuberculosis is false. The Farmer's 
Companion and Horticultural Gazette for 1852 mentions con- 
sumption as one of the most dangerous diseases of cattle and 
one which "will become mortal if not immediately attended 
to." The report of the Massachusetts Society of Agriculture 
for 1880 points out that certain cases of suspected contagious 
pleuro-pneumonia of cattle were cases of tuberculosis. There 
are very few references to tuberculosis in cattle in this country 
prior to 1865; indeed the agricultural and veterinary litera- 
ture* contains little about this disease until after Koch had 
discovered its cause in 1882. Attention was centered on 
tuberculosis in cattle in 1890 when it was found that tuberculin 
caused a reaction in many animals apparently healthy but 
on post mortem found to contain somewhere in their bodies 
small or larger active tubercles. 

In 1907, in order to determine the extent to which the 
disease had spread in certain dairy districts of New York, I 
collected the results of a number of tests that were made during 
that and previous years, but largely in 1907, by a considerable 
number of veterinarians to whom tuberculin had been furnished. 
The results showed that of 421 herds tested, 302 contained 
cattle that reacted. These herds contained a total of 9,633 
animals, of which 3,432 reacted. The herds were distributed 
in 39 counties. The greater number of the tests were made for 
one or the other of the three following reasons, namely: (1) when 
the herd was suspected of being diseased; (2) when the pur- 
chasers of animals required the test before accepting the 



*The Veterinarian (London) in 1830 (Vol. VI) describes the symptoms 
and treatment of consumption in cows. 



DISTRIBUTION, ECONOMIC AND SANITARY IMPORTANCE 7 

cattle; and (3) when the purchasers of the milk or its pro- 
ducts required that the cows should be tuberculosis free. 

The official tests by the State Department of Agriculture 
for the years 1904-6 inclusive, kindly furnished me by Dr. 
Kelly then acting Chief Veterinarian, include 262 herds with 
a total of 3,088 animals, of which 673 reacted. They were 
distributed in fifty counties. These herds all came under the 
operation of the law. Infected animals were found in 121 
herds. 

The reliable available data for New York State at that 
time were restricted to 683 herds, aggregating 12,721 animals, 
distributed in fifty counties. Of the 683 herds, 423 contained 
reacting individuals. A small percentage of the reactors gave 
physical evidence of being diseased. Although these figures 
show a somewhat extensive infection of the herds examined 
it must be remembered that they represented only about 
one-half of one per cent of the cattle of the State, and those 
from the sections presumably most highly infected. 

The reports of tuberculin tests in other states show that in 
dairy districts where the herds have been built up by the 
indiscriminate purchase of cows the disease is quite prevalent. 
The number of animals that are infected can not be deter- 
mined as but a small percentage of them are tested. It 
seems to be very clearly established that there are localities 
where it is much more prevalent than elsewhere. It is also 
clearly shown that there are many places where farmers have 
not bought cattle from without, at least to any appreciable 
degree, and that tuberculosis is rare in these localities. The 
fact, however, that it has been reported from nearly if not all 
dairy districts in the United States warrants the general 
assertion that it is widespread. 

In considering the economic importance of tuberculosis 
among cattle the essential fact relative to its distribution 
must be kept in mind. When it is once introduced, it is liable 
to spread from infected to well animals with more or less 
rapidity. 



8 BOVINE TUBERCULOSIS 

The time necessary for a tuberculous cow to infect a large 
percentage of the cattle in the herd depends upon the rapidity 
with which the lesions in the infected animal develop to the 
stage where the tubercle bacteria are thrown off. There is 
a great difference in the length of time required for this de- 
velopment. In some cases the tuberculous areas become 
surrounded with a wall of fibrous tissue which checks the 
growth and the animal may never show evidence of its pres- 
ence. In other animals the infection may result in the rapid 
spread of the disease within the body and in the course of a 
few weeks or months tuberculous areas may discharge into 
some channel of excretion and the organisms be eliminated 
with either the saliva, feces, uterine discharges or the milk. 
It is impossible, therefore, to predict when a cow that reacts 
to tuberculin but appears to be perfectly well physically will 
spread the virus. This difference in the rapidity with which 
the disease develops depends upon the virulence of the infect- 
ing organism and the resistance of the animal. Pathogenic 
bacteria such as those of tuberculosis are not always possessed 
of the same degree of disease producing power. The resisting 
power of different individuals and even of the same individual 
under different conditions varies. It is impossible in the 
natural course of infection to determine the degree or extent 
of either of these factors. If this phase of the disease is under- 
stood it will explain why some animals that react continue 
to remain apparently well, while others develop physical 
signs of the disease and infect many individuals in the herd 
within a period of a few months. While these facts pertain 
to the nature of the disease, they are important in this con- 
nection to explain why some herds become infected rapidly 
and others more slowly or not at all after the introduction of 
a reacting animal or animals. 

Economic Importance. It is difficult to estimate the loss 
from bovine tuberculosis. There are many ways in which it 
operates financially against owners of livestock. Briefly 
stated, they are as follows: 



DISTRIBUTION, ECONOMIC AND SANITARY IMPORTANCE 9 

1. By destroying cattle outright, as when tuberculosis 
is allowed to reach its full development and kill its victim. 

2. By reducing the market value of the animal, as in 
those cases in which the beast is sold before the disease has 
reached such a stage as to render it entirely unmarketable. 

3. By reducing the breeding value of a herd and its gen- 
eral productivity. 

4. By causing a waste of cattle food by feeding animals 
that can not give an adequate return. 

5. By infecting other animals such as calves, swine and 
other cattle through the milk and by direct contact. 

6. By injuring the reputation of the herd, thereby ren- 
dering it difficult to dispose of the animals or their products. 

7. By destroying the enthusiasm or interest of the breeder 
in the maintenance of his herd at a high standard. 

In reference to the first two of these points it may be said 
that careful statistics gathered some time ago by Siedam- 
grotzky in Germany show that the cattle industry of that 
country was taxed to the extent of 6,762,660 marks per year, 
as a result of condemnation of carcasses and destruction of 
parts of carcasses, in slaughter houses; and these figures do 
not begin to represent the total loss from tuberculosis in that 
country. Renneberger estimated that the total loss amounted 
to more than 90,000,000 marks annually. This was considered 
a conservative estimate. It is recognized that tuberculosis 
injures the livestock industry in Germany to a far greater 
extent than any other pest, and this includes such exceedingly 
virulent affections as rinderpest, lung plague, foot-and-mouth 
disease, anthrax and others. 

"The slaughter-house statistics of Prussia show 14.6 per 
cent of the cattle and 2.14 per cent of the hogs to be tubercu- 
lous. In Saxony the percentage is 29.13 for cattle and 3.10 for 
hogs. In the city of Leipzig, the figures are 36.4 per cent for 
cattle and 2.17 per cent for hogs (Siedamgrotzky). Of 20,850 
animals in Belgium tested with tuberculin in 1896, 48.88 per 
cent reacted (Stubbe). Of 25,439 tested in Denmark from 1893 



10 BOVINE TUBERCULOSIS 

to 1895, 49.3 per cent reacted; and of 67,263 tested from 1896 
to 1898, 32.8 per cent reacted (Bang). An examination of 
20,930 cattle in Great Britain, either slaughtered and exam- 
ined post-mortem or tested with tuberculin, showed 5,441, 
or 26 per cent, affected with tuberculosis. MTadyean estimates 
that 30 per cent of the cows in Great Britain are tuberculous." 

The amount of tuberculosis found in the food animals by 
the Government veterinary inspectors in this country is enor- 
mous. During the fiscal year 1905, there were inspected 
6,134,388 carcasses of beef animals, of which 10,956 were con- 
demned for this disease. The increase of tuberculosis in hogs 
is shown by the fact that in 1900, of 23,336,884 hogs that 
were inspected, 5,440 were affected sufficiently to cause a con- 
demnation of some one or more parts of the carcass. In 1905, 
of 25,357,425 hogs inspected post mortem, 64,919 carcasses 
and 142,105 parts of carcasses were condemned for tubercu- 
losis. I am told that last year (1911) one packing house lost 
$154,000 worth of hogs from this disease. It should be remem- 
bered that these condemnations were made on the inspection 
of hardly a third of the animals killed in the United States 
for human food. It is also important to note that these inspec- 
tions were made on animals slaughtered in our larger packing 
houses and that these animals were in a better general condi- 
tion than many which are slaughtered locally. 

In 1908, Dr. Melvin, Chief of the Bureau of Animal Indus- 
try, made the following significant statement at the Congress 
on Tuberculosis in Washington. ^ 

"While the saving of human life affords the highest motive 
for combating tuberculosis, the prevention of financial loss 
is alone a sufficient reason for undertaking the eradication 
of the disease from farm animals. Statistics of the United 
States Federal meat inspection for the fiscal year ending June 
30, 1908, covering 53,973,337 animals, or more than one-half 
of all those slaughtered for food in the country, show the 



iMelvin. Am. Vet. Review, Vol. XXXIV (1908) p. 250. 



DISTRIBUTION, ECONOMIC AND SANITARY IMPORTANCE 11 

following percentage of tuberculosis: Adult cattle, 0.961; 
calves, 0.026; hogs, 2.049; sheep and goats, 0. The propor- 
tion of tuberculosis is probably higher in animals slaughtered 
without inspection. Reports of tuberculin tests made in the 
15 years from 1893 to 1908 by Federal, State and other officers 
with tuberculin prepared by the Bureau of Animal Industry 
have been carefully analysed and tabulated. Out of 400,000 
cattle tested (mostly dairy cattle) there were 37,000 reactions, 
or 9.25 per cent. From these two classes of statistics it is 
concluded that on the average about 10 per cent of the milch 
cows, 1 per cent of other cattle, and 2 per cent of the hogs 
in the United States are affected with tuberculosis, the average 
percentage for all the cattle being estimated at 3.5. 

"The accuracy of the tuberculin test has been confirmed 
in a remarkable way by post mortem examinations. Out of 
23,869 reacting cattle slaughtered, lesions of tuberculosis 
were found in 23,585, a percentage of 98.81. Properly pre- 
pared tuberculin applied by a competent person is therefore 
shown to be a wonderfully reliable agent for diagnosing tuber- 
culosis. In cases where the test appears to give unsatis- 
factory results, this is usually due to the use of a poor quality 
of tuberculin or to ignorance or carelessness in applying it. 

"The economic loss on account of tuberculosis in food- 
producing animals is heavy. The loss on animals in which 
tuberculosis is found in the Federal meat inspection is esti- 
mated at $2,382,433 annually, and if the same conditions were 
applied to animals slaughtered without Federal inspection 
the annual loss on all animals slaughtered for food in the 
United States would be increased to $3,102,433. The stock 
of animals on hand is also depreciated in value because of 
tuberculosis. Assuming that living tuberculous milch cows 
are annually depreciated to the extent of one-tenth of what 
the loss would be if they were slaughtered, other cattle one- 
third, and hogs one-half, the total animal depreciation amounts 
to $8,046,219. The annual loss from decrease in milk pro- 
duction is estimated at $1,150,000, and there also is some 



12 BOVINE TUBERCULOSIS 

loss from impairment of breeding qualities. Taking all these 
items into account, the aggregate animal loss because of tuber- 
culosis among farm animals in the United States is estimated 
at not less than $14,000,000. 

"Such heavy financial losses make the eradication of tuber- 
culosis from farm animals desirable purely as an economic 
matter." 

Sanitary importance. The sanitary significance of bovine 
tuberculosis has been the subject of many investigations and 
more or less heated discussions. There is a voluminous liter- 
ature on the subject but the findings of the last few years have 
established more definite facts concerning it than the opinions 
previously entertained. 

When Koch discovered the tubercle bacterium to be the 
specific cause of tuberculosis he believed that the tubercle 
organisms found in cases of tuberculosis in man and of cattle 
were identical. This conclusion was supported by many 
workers on tuberculosis and the belief grew up among not 
only bacteriologists and physicians but also among laymen 
that tuberculosis in cattle was transmitted to man. There 
were those who believed further that human tuberculosis was 
not infrequently conveyed to cattle. The significance of this 
belief began to be appreciated after the discovery of tuber- 
culin and the finding of such a large percentage of apparently 
healthy cattle to be infected. The findings of Smith that 
there were distinct differences between the human and the 
bovine varieties of tubercle bacteria showed that there is not 
so much infection of the human species with the bovine variety 
of tubercle bacteria as was formerly supposed. His findings, 
together with the results of many other investigators, seem to 
warrant the conclusion that adults are rarely if ever infected with 
the bovine type but that young children suffer to a considerable 
extent from tubercle infection of bovine origin. Park and 
Krumwiede^ summarized the literature of others together with 

^Park and Krumwiede. Collected Studies from the Research Laboratory, 
Dept. of Health, City of New York, Vol. V (1910). 



DISTRIBUTION, ECONOMIC AND SANITARY IMPORTANCE 13 

their own results relative to the age of the persons infected 
and the source of the virus. They found from the cases that 
had been carefully studied bacteriologically that of the 389 
tuberculous human subjects 16 years of age or older but 8 were 
infected with the bovine type. These were in tuberculosis of 
the abdominal organs, glands and bones. Of 78 tuberculous 
children between the ages of 5 and 16 years 24 were infected 
with the bovine variety, and in 136 tuberculous children 
under 5 years of age 37 were infected with the bovine type 
of tubercle bacteria. Dr. Park states that from 200 to 300 
children die in New York City annually with tuberculosis 
of the bovine variety. This is a heavy toll to pay for infected 
milk from a disease that can by a little care be prevented. 

Many questions have arisen relative to the possible change 
in the type of the tubercle organism by passing it through the 
tissues of different species of animals. A large amount of 
experimental work has been done along this line. The results 
tend to show that certain modifications take place in the 
characteristics of the organisms but that these changes* are not 
rapid or sufficiently constant to warrant the conclusion that 
either the human or bovine type is transformed into the other 
during its passage in the body of the individual. There are, 
however, some experiments that tend to such a conclusion. 



*Park and Krumwiede {loc. cit.) have summarized the results of experi- 
ments along this line and given the results of their own work. Those who 
are interested in this phase of the biology of tubercle bacteria will do well to 
refer to the report mentioned. 



CHAPTER III 

The Cause of Tuberculosis in Cattle 

In 1882, Robert Koch^ discovered the cause of tubercu- 
losis to be a microorganism which he called the bacillus of 
tuberculosis. It is a slender rod-shaped organism. It is not 
motile and it does not produce spores. The more recent 
classifications of bacteria place this organism in the genus 
Bacterium because of its non motility. In the earlier classifi- 
cations it was placed in the genus Bacillus. It is therefore 
referred to in the literature on the subject sometimes as a 
bacterium and sometimes as a bacillus. 

Bacterium tuberculosis appears as a slender rod ,1.5 to 4.0 
microns* in length and from 0.2 to 0.5 microns in width. The 
organisms may be straight or slightly curved. As a rule, the 
curve is more pronounced in the human variety. The diam- 
eter is quite uniform throughout its length. In the human 
variety, especially as found in tuberculous sputum, they 
are quite frequently beaded and stain somewhat irregularly. 
The unstained areas are regarded as vacuoles. The bovine 
variety is slightly shorter than the one from man. It is usually 
from 1.5 to 3 microns in length and from 0.3 to 0.8 microns 
in thickness when found in the tissues, milk or excreta. They 
do not so frequently present irregularly stained areas. A 
number of observers have found branched forms of tubercle 
bacteria 2. 

The tubercle bacterium does not stain readily with the 

*Koch. The etiology of tuberculosis. Mittheilungen aus dem Gesund- 
heitsamte, Bd. II (1884). Translated by Stanley Boyd and published among 
the essays by various authors on Bacteria in Relation to Disease. In the 
volumes issued by the New Sydenham Society. London, 1886. 

*A micron is a unit for microscopic measurement. It is 1/1,000 of a 
millimeter or 1/25,000 of an inch. 

*Nocard and Roux. Ann. de I'lnst. Pasteur, 1887. 



THE CAUSE 15 

ordinary aniline dyes used for staining bacteria. Once 
stained, however, the dye is retained, even after the appHca- 
tion of alcohol and acids. It is for this reason that they are 
spoken of as "acid proof" bacteria. The chemical analyses 
of tubercle bacteria show that surrounding the organism 
or existing in its outer layers or cell wall there are fatty acids. 
This has given rise to the term "acid fast" as it is supposed 
that there is some combination between the coloring matter 
and these fatty acids preventing the bacteria giving up their 
stain when treated with solutions of mineral acids. The dyes 
that have been used successfully to stain this organism are 
Ehrlich's solution of aniline-water gentian-violet and Ziehl's* 
carbol fuchsin solution. Much found a bacterium resembling 
that of tuberculosis morphologically but which did not retain 
the stain when treated with the decolorizing solutions. He 
refers to it as a non acid-fast tubercle bacterium. In staining 
Bacterium tuberculosis, therefore, the preparation must be 
first deeply stained and then treated with a solution of a min- 
eral acid such as nitric or sulphuric and thoroughly washed. 
The tubercle bacteria, if present, will remain deeply stained 
while the other bacteria and tissues will be decolorized. The 
preparations may be counterstained with methylene blue, in 
which case the other bacteria and tissues will be colored. 
Gabbett combined decolorization and counterstaining in 
one solution. This consisted of methylene blue 1 gram; 
cone, sulphuric acid 25 grams; and distilled water 100 cc. 
After staining in the carbol-fuchsin solution the preparations 
are covered with this decolorizer for a few seconds and washed 

*This consists of 

Fuchsin (dry) 1 gram 

Alcohol (absolute) 10 cc. 

Carbolic acid (5% solution) 100 cc. 

Dissolve the fuchsin in the alcohol, after which add the carbolic acid 
solution. Instead of using the dry fuchsin and alcohol, 11 cc. of a saturated 
alcoholic solution fuchsin may be used. If the mixture is not clear, add 
more of the saturated alcoholic solution of fuchsin drop by drop until when 
viewed through the pipette by transmitted light the liquid is perfectly clear. 



16 BOVINE TUBERCULOSIS 

in water. The tissues and other bacteria will be stained blue. 
It has been found that a large number of saprophytic acid- 
fast bacteria will become decolorized if treated with a 3 per 
cent solution of hydrochloric acid in 95 per cent alcohol. 

Tubercle bacteria are cultivated without difficulty on 
blood serum, egg medium, glycerin bouillon and potato, 
after they have been accustomed to artificial cultivation. 
They are not readily obtained in pure culture from tubercu- 
lous tissues. Smith found that by inoculating guinea pigs 
with the suspected material and as soon as the disease had 
begun to develop chloroforming the pigs and transferring 
quite large pieces of the diseased organs, such as spleen or 
liver, directly to the surface of dog serum (coagulated at 
72° C.) and placing them in the incubator at 37.5° C. in 
which there was considerable moisture, the multiplication 
of the bacteria continues and in some days visible growth 
appears on the serum at the edges of the tissue. Some workers 
have little difficulty in the use of ordinary beef serum. The 
Dorset egg medium is also used by some workers for this 
purpose. 

Growth of tubercle bacteria. On blood serum at 37.5° C, 
colonies usually become visible at the end of from eight to 
fourteen days. They appear at first as small, dry, grayish- 
white, scaly spots with corrugated surfaces. After three 
or four weeks' cultivation, these join together, covering the 
surface of the medium as a dry, whitish, wrinkled membrane. 
Coagulated dog serum is regarded by Theobald Smith as 
one of the most favorable media for the growth of tubercle 
bacteria. 

Glycerin bouillon (made of beef or veal with peptone one 
per cent, glycerin 5 per cent, and rendered slightly alkaline) 
is an extremely favorable medium after it has been cultivated 
for a few generations on blood serum or egg medium. The 
bouillon should be in shallow layers, in wide mouthed flasks, 
as the free access of oxygen is essential for growth. The 
inoculation of this medium should be made by carefully 



THE CAUSE 17 

floating flakes of the growth upon the surface. In multiplying, 
the bacteria will spread out upon the surface, at first as a 
thin, opaque, floating membrane which rapidly thickens into 
a whitish wrinkled or granular layer, covering the entire 
surface of the fluid in from four to six weeks. Later, por- 
tions of the membrane may sink to the bottom. In old 
cultures, the membrane assumes a yellowish hue. These 
cultures emit a peculiar aromatic odor. It is from cultures 
of this kind that tuberculin is made. 

In 1898, Theobald Smith ^ published the results of his 
researches into the relation of human and bovine tubercle 
bacteria. He found, contrary to all previous statements, 
that there were well marked morphological, cultural and 
pathogenic differences between them. In 1901 Koch* read 
his famous paper in which he gave the world to understand 
that there was no relation existing between human and bovine 
tubercle bacteria. With that announcement there began 
one of the most intense investigations into the nature of a 
disease that has ever been recorded. For ten years a large 
number of competent men and women have been carrying on 
researches covering every conceivable phase of this great 
malady. The findings are quite unanimous in pointing out 
two distinct varieties of mammalian tubercle bacteria, one 
in man, the other in cattle, and in showing that children are 
sometimes infected with the bovine variety. 

The disease producing power of the different varieties 
of Bacterium tuberculosis varies. The human and bovine 
varieties appear to be equally virulent for guinea pigs. The 
lesions produced are quite characteristic and can be identified 
usually by the gross appearance or by microscopic examination 
of the structure of the changed tissue. The human variety 
is not usually fatal to rabbits, cattle, or other animals and 
frequently the tissue changes which it produces are very 
slight and restricted to the point of inoculation. The bovine 

" 'Smith. Jour. Exper. Med.. Vol. Ill (1898) p. 451. 

*Koch. Translated in Am. Vet. Review, Vol. XXV (1901) p. 441. 



18 BOVINE TUBERCULOSIS 

variety is usually fatal to rabbits and cattle. When fed milk 
containing tubercle bacteria horses frequently develop tuber- 
culosis.* Swine are very susceptible to the bovine variety. 
Sheep, goats, cats and dogs are less susceptible although 
cases of tuberculosis are recorded in these species. The avian 
variety is virulent for fowls. Moore ^ was unable to produce 
tuberculosis in guinea pigs with the avian culture or to produce 
tuberculosis in fowls with the human and bovine varieties by 
feeding or by subcutaneous inoculation of pure cultures or 
of tuberculous sputum or tissue. Both Nocard and Johne, 
however, report producing the disease in fowls with human 
and bovine tuberculous tissue. Natural infection seems to 
take place through the respiratory and digestive tracts. There 
is a pronounced difference of opinion as to the relative fre- 
quency of infection by these channels. 

Acid-fast bacteria. In addition to the question of identity 
or non-identity of human and bovine tubercle bacteria, 
extended researches have shown the existence of many "acid- 
fast" bacteria widely distributed in nature that can not 
be differentiated morphologically or by their staining prop- 
erties from true tubercle bacteria. 

These have been found in considerable numbers in milk, 
butter, feces, on timothy hay, in water and elsewhere. Peter- 
son^ found that the differentiation between tubercle bacteria 
and certain other "acid- fast" bacteria that frequently appear 
in the milk and feces of cattle can not be made by the known 
methods of decolorization such as acidulated acohol and 
strong solutions of nitric acid. 

Much^ and more recently Schroeder^ have described 
non-acid fast organisms that produce a disease in guinea 



*In Denmark where horses are given more or less milk, tuberculosis is 
quite common. We have had one case only of this disease in a horse. 
^Moore. Jour. Med. Research, Vol. XI (1904) p. 521. 
^Peterson. Report of N. Y. State Veterinary College, 1909-10, p. 65. 
'Much. Beitr. z. Klinik der Tub., Bd. IX, S. 415. 
^Schroeder. Proceedings Am. Vet. Med. Asso., 1911. 



THE CAUSE 19 

pigs with lesions apparently not unlike those of tuberculosis. 
Thus each of the properties of tubercle bacteria, its supposed 
specific stain and its effect upon the tissues of guinea pigs, 
that had long been recognized as possessing diagnostic 
value, has been found to be insufificient in itself. These find- 
ings have brought clearly before us the phenomenon of the 
"acid-fast" group of bacteria and the difficulty of diagnosing 
tuberculosis by finding an organism that possesses the right 
morphology and retains the stain when treated with a de- 
colorizing reagent. 

OTHER PATHOGENIC ACID-FAST BACTERIA 

Johne's disease {chronic bacterial enteritis in cattle). In 
1895, Johne and Frothingham^ described a chronic disease 
in cattle characterized by intestinal disturbances and pro- 
nounced wasting of flesh and a thickening of the mucous 
membrane of the affected portions of the intestine. Mor- 
phologically, this organism resembles the tubercle bacterium. 
It varies in size from 1 to 2 microns in length, although individ- 
uals of 4 microns have been observed. The bacteria are not 
particularly intracellular but are found lying free, both single 
and in chains, in the spaces between the cells and fibers. In 
old lesions the bacteria are more numerous than in the early 
stages of the disease. 

This was at first thought to be avian tuberculosis in cattle. 
MTadyean^'^has described this disease in England. It has 
been found a number of times in this country. Olaf Bang ^ ^ 
found that cattle suffering with this disease gave a reaction 
to tuberculin prepared from the avian variety of tubercle 
bacteria. They do not react to tuberculin prepared from the 
human or bovine varieties. 

This organism is worthy of careful consideration, as the 
disease it causes is quite widely distributed in the United 



9johne and Frothingham. Zeit. f. Tiermedizin, Bd. XXI (1894)s S. 438. 
loM'Fadyean. Jour, of Comp. Path, and Therap., Vol. XX (1907) p. 48. 
I'Olaf Bang. Ninth International Vet. Congress, The Hague, 1909. 



20 BOVINE TUBERCULOSIS 

States. It is reported to be quite prevalent on the Island of 
Jersey. Mr. Olaf Bang of Copenhagen told me recently that 
when buyers from Denmark bought cattle on that island 
they tested them with avian tuberculin in order to avoid 
purchasing animals suffering with this affection. 

Stockman 12 h^s described "acid-fast" bacteria similar to 
those of Johne's disease, in the intestines of sheep suffering 
from a like disease. In scrapings from the intestine, bac- 
teria appeared in great numbers and in dense clumps as in 
Johne's affection. They were also foimd in the mesentery 
lymphatic glands. Sections of the glands failed to show any 
tissue changes suggestive of the formation of tubercles. 

Leprosy-like bacteria in animals. The bacterium of leprosy 
is an acid-fast organism that seems to be somewhat closely 
related to the tubercle bacterium. In the extent of the bac- 
teria in the diseased tissue Sibley has called attention to the 
similarity between leprosy and avian tuberculosis. 

Dean^^ investigated a disease of rats in England resem- 
bling leprosy in which he found enormous numbers of acid- fast 
bacteria in the cells which, however, he could not cultivate. 
This leprosy-like disease of rats was first described by Ste- 
fanskyi* in 1903. He pointed out two distinct types, one in 
which the skin and musculature were involved and the other 
where the lesions were confined to the lymphatic glands. 

Wherry 1^ found in a study of the leprosy disease of rats 
that the organisms were taken up by flies that fed upon the 
carcasses of the leper rats. He showed that flies thus infected 
deposited the organisms with their feces. They did not mul- 
tiply in the intestine of the flies and they were practically 
eliminated within 48 hours. He experimented with the green 
bottle fly (Lucilia Caesar), blow fly {Caliphora vomitoria) 
and the house fly (Musca domestica) . He calls attention to 

>2Stockman. Jour, of Comp. Path, and Therap., Vol. XXIV (1911) p. 66. 
i^Dean. The Jour, of Hygiene, Vol. V (1905) p. 99. 
i^Stefansky. Centralbl. f. Bakt., Bd. XXXIII (1903) S. 481. 
i^Wherry. Jour, of Inf. Dis., Vol. V (1908) p. 507. 



THE CAUSE 21 

the value of rat leprosy in studying the role that parasitic 
insects may play in the transmission of leprosy bacteria. 

It is clear that the differentiation of the tubercle organism 
from the many other bacteria which resemble it in morphology 
and which retain the stain when treated with decolorizing 
agents in a manner similar to the tubercle organism, is a far 
more difficult task than was originally supposed. This 
calls for greater care on the part of the laboratory worker. 
The conclusion seems to be justified that there has been more 
or less of error in the reports of finding tubercle bacteria in 
various materials when the identification was made on the mi- 
croscopic examination only. While it is true that the usual 
methods give in most cases accurate results in diagnosing 
tuberculosis, the present knowledge of the group of "acid- 
fast" bacteria demands very careful checking up of methods 
in all unusual cases or those in which doubt as to the true 
nature of the organism may exist. 



CHAPTER IV 

The Nature of Tuberculosis and the Changes 
Produced in the Tissues by Tubercle Bacteria 

Tuberculosis is the name given to the condition resulting 
from the growth of tubercle bacteria in the tissues. The 
name comes from the Latin tuberculum meaning a tubercle 
which signifies a rounded prominence. In anatomy the term 
is used to designate a rounded prominence on bone or in soft 
tissues. In cases of tuberculosis one often finds round smooth 
prominences protruding from the serous membranes lining 
the larger cavities of the body. Because of the frequency 
of the small prominences the Germans refer to this form of 
tuberculosis as "pearl disease." 

Bacteria are known to cause disease in two distinct 
ways, namely, by producing a virulent toxin that poisons the 
tissues and by multiplying in the tissues and destroying them. 
There are many intermediate variations but generally speak- 
ing diseases caused by microorganisms are due to the produc- 
tion of toxins or to the destruction of the tissues in which the 
bacteria are multiplying. Diphtheria and tetanus or lock 
jaw are good illustrations of the first and tuberculosis and 
leprosy of the latter method. 

All infectious diseases are divided into three quite distinct 
periods or stages. The first is that immediately following 
infection and known as the period of incubation. This is 
the time required for the organisms to become established in 
the tissues. It is measured from the time they get into the 
body until the symptoms appear. In most infectious diseases 
this time varies from a few to fourteen days. The second 
period is the duration of the disease, that is, the time from 
the appearance of the first symptoms until death or the begin- 
ing of recovery. This time varies from a few days to many 
weeks, months or years. The third or last period is known 



NATURE OF CHANGES PRODUCED 23 

as convalescence and it covers the time from the disappearance 
of the symptoms until recovery is complete. It also varies 
in length of time. 

In order to have a clear understanding of the kind of 
disease tuberculosis is, it may be well to compare it with some 
affection that is more commonly recognized as infectious. 
For this we may take diphtheria in children. It is well known 
that diphtheria is caused by a micro-organism, Bacterium 
diphiheriae. It is also known that when a healthy child is 
exposed (infected) by being brought in contact with a child 
sick with diphtheria, the period of incubation is but a few 
days, and that the duration of the disease is short, lasting 
but a few days or weeks at the longest. At the end of that 
short period, the entire course of the disease has been run 
and the child is either dead or well on the way to recovery. 

In tuberculosis the periods in the course of the disease 
differ in detail from those in diphtheria in three very impor- 
tant points, namely, the length of the period of incubation, 
the way in which the specific bacteria produce the disease, 
and the time required for it to run its course, or its duration. 
With diphtheria the specifxC bacteria produce a toxin which 
poisons the tissues, and this toxin is the cause of the symptoms, 
and in fatal cases, of death. In tuberculosis, the specific bac- 
teria do not produce such a toxin, but they live in one or 
more of the tissues of the body, multiply there, and by their 
multiplication penetrate deeper and deeper into the organs 
of the body, destroying the tissues as they go. Finally the 
injured organs, because they cannot properly perform their 
functions, give rise to symptoms at first slight, but grad- 
ually becoming more and more serious. Death is produced 
because some organ or part necessary for the life of the indi- 
vidual has been destroyed.* While diphtheria completes its 



*In the human subject it frequently happens that secondary infection 
with streptococci or other septic bacteria is the immediate cause of death. 
This condition does not seem to occur so frequently in cattle. 



24 BOVINE TUBERCULOSIS 

course in a few days or weeks, tuberculosis requires for the 
same purpose months and more often years. 

The usual direct anatomical changes following the inva- 
sion of tubercle bacteria are the formation of nodules or tuber- 
cles. A tubercle has been defined as "a small non- vascular 
nodule composed of cells varying in form and size with some 
basement substance between them and with an inherent 
tendency to undergo central necrosis." In a large number 
of cases the individual tubercles are distinct and easily recog- 
nizable, while in others they are coalesced, forming a mass of 
necrotic tissue. The lesions vary, therefore, from well iso- 
lated minute or "arger nodules to masses or cavities contain- 
ing a purulent, caseous, or calcified substance. 

The location of the first or primary lesion depends upon 
the channel of infection. If the specific organisms are lodged 
in the mouth or pharynx, they may, through an accidental 
abrasion of the mucous membrane, be taken to some of the 
lymphatic glands about the head; if they are taken directly 
through the respiratory passages into the lungs they either 
develop nodules in the lung tissues proper, or they are carried 
through the lymphatic system to the lymph glands draining 
the iungs where the lesions first appear. If the specific bac- 
teria are first lodged in the mucous membrane of the intes- 
tine, primary tuberculous ulcers may develop in the intestine 
or the bacteria may pass into the mesenteric lymphatics or 
the portal vein. They may be carried through the thoracic 
duct into the general circulation and by the blood to any 
part of the body, such as the brain, liver, kidneys, spleen, 
testes, ovaries, joints, and subcutaneous and intermuscular 
glands and serous membranes. The evidence at hand, how- 
ever, seems to show that in a large majority of cases the first 
or primary tissue changes are located in one or the other of 
the five following organs:* (1) in the lungs or the lymphatic 
glands draining them, (2) in the lymphatic glands about the 

*For a detailed study of the lesions in bovine tuberculosis see Bulletin 
No. 7, Bureau of Animal Industry, 1895, by Theobald Smith. 



NATURE OF CHANGES PRODUCED 25 

head, (3) in the mesenteric glands and intestines, (4) in the 
portal glands or liver substance itself, and (5) in the gener- 
ative organs and udder. 

It not infrequently happens that the apparent primary- 
lesions occur on the pleura, peritoneum, meninges or synovial 
membranes while the organs remain free from disease. In 
such cases the lesions consist of many tubercles var^dng from 
one to ten or more millimeters in diameter or of bunches of 
closely set tubercles which are more or less flattened or irreg- 
ular in shape, owing to their mutual pressure. Sometimes 
these tubercles are attached to the serous membrane by a 
small, tough, fibrous pedicle; frequently, however, this is 
absent and the nodules rest upon the membrane. 

The structure of the tubercle. The tubercle consists in the 
beginning of a few cells surrounding the invading specific 
organisms. These are soon encased by a zone of epithelioid 
cells and giant cells which is soon surrounded by an outer 
layer of round or lymphoid cells. The central portion becomes 
necrosed and as the nodule enlarges the central necrotic por- 
tion becomes correspondingly large. See Plate IV. 

This histological structure of the tubercle is typically 
illustrated in the early stages of the avian tubercle. In most 
animals there is a tendency to rapid destruction of the tissue 
but in the fowl the process usually requires more time. In 
cattle there is a strong tendency for the necrotic tissue to 
become infiltrated with lime salts. In certain species a de- 
posit of fibrous tissue in the outer zone of the tubercle has 
been observed. In the smaller and more susceptible experi- 
mental animals such as the guinea pig and rabbit and fre- 
quently in swine, the lesions are of a more diffuse nature 
extending into the connective tissue and gradually encroach- 
ing upon the cells of the organs. Circumscribed tubercles may 
also be present. 

In secondary or generalized tuberculosis one or more oj 
the organs, such as the lungs, omentum, serous membranes, 
or lymphatic system, may become more or less thickly 



26 BOVINE TUBERCULOSIS 

sprinkled with minute grayish nodules about the size of a 
millet seed. These tubercles are at first almost the color of 
mother-of-pearl but later as the central caseous degeneration 
begins they become grayish. Giant cells are usually numerous. 
In studying the lesions in a fatal case of tuberculosis one 
may find with varying modifications one or more of the fol- 
lowing conditions: 

1. The primary tubercle may be found in any one of the 
organs or membranes. Its relative age can be determined 
by the character of the changes and the production of tissue 
about it. It may be entirely encysted, caseous or dead and 
calcareous. In addition to the primary focus, there may be 
a succession of tubercles of various ages distributed in one or 
more organs. 

2. The tubercles may be restricted to one organ, as the 
liver, in which the primary focus has spread by continuity 
due to its infiltrating nature until the destruction of the 
tissues of the organ has become so extensive that death results. 
Such cases do not seem to be common. 

3. The primary lesion may be well marked and accom- 
panied by miliary tubercles sprinkled extensively throughout 
the organs and tissues of the entire body. 

4. The lesions throughout the body may resemble each 
other very closely, so that difficulty may be experienced in 
determining the primary focus. 

In the lungs, two distinct forms of tissue changes have 
been observed. (1) The air cells may be infiltrated with the 
tuberculous mass spreading directly from the primary focus. 
This may be purulent, caseous or calcareous. The color may 
be whitish, gray or of a yellowish tinge. (2) The lesions may 
consist of miliary tubercles. In later stages these nodules, 
more or less translucent, may become yellowish, caseated, 
and calcareous in their centers. Large tuberculous nodules 
are frequently formed by the massing of several of the small 
tubercles. 



NATURE OF CHANGES PRODUCED 27 

When the lungs are primarily affected the large or prin- 
cipal lobes are most frequently involved. Smith considers 
the seeming predilection for the larger lobes to be due to 
mechanical conditions. The writer has found, however, 
that in certain herds that have been killed after the tuber- 
culin test, the primary and only lung lesions of sufficient 
size to be recognized were in the ventral and cephalic lobes. 
It is important to note that usually the bronchial glands are 
also involved. When the serous membranes covering the 
lungs or intestines are affected, the lesions consist of nodules 
varying in size from that of a millet seed to a large pea, sprinkled 
more or less thickly on one or both of the visceral or parietal 
surfaces. These form the "pearl disease" (Perlsucht) of the 
German and the "grape disease" of the English writers. If 
they become confluent, large masses are found. 

Tuberculosis of the thoracic glands is very common and 
usually accompanies lesions in the lungs; but the lungs 
may be healthy and the glands involved. The primary lesions 
may be and often are found in the lymphatic glands about the 
head. 

In the abdominal cavity the organs most frequently 
involved are the peritoneum, mesenteric l^inph glands, portal 
lymph glands and liver. The kidneys, spleen, ovaries and 
uterus are more rarely the seat of tuberculous lesions. Ulcers 
in the intestine have not been common in the writer's obser- 
vation. The ulcers in the cases observed have been isolated, 
with elevated borders and a depressed center. Sections 
show that the tuberculous infiltration extends outward, and 
to a certain extent undermines the mucosa. Tuberculosis 
of the testis is sometimes found. The udder becomes the seat 
of tuberculous deposits in a small percentage of cases. It 
is more often afifected in cases of generalized tuberculosis. 

When the primary infection is restricted to a single focus 
the disease is said to be localized. When the specific bacteria 
are spread from the primary lesions through the agency of 
the lymph and blood streams, sprinkling other organs with 



28 BOVINE TUBERCULOSIS 

the infecting bacteria, each of which becomes the starting 
point for the development of a new tubercle, the disease has 
become generalized. * 

It was formerly considered that when the lesions existed 
in both of the large (abdominal and thoracic) cavities of the 
body the disease was generalized. It is possible, however, 
for it to be generalized when the lesions are restricted to the 
organs of one cavity, as the secondary seeding with the bac- 
teria that have escaped from a primary focus through the 
circulation may be restricted to the cavity in which the first 
lesion developed. It seems better, therefore, to accept Oster- 
tag's views and classify local and generalized tuberculosis in 
accordance with the nature of the lesions rather than their 
distribution in the body. 

The fact is worthy of consideration, that very often cattle 
killed after reacting to tuberculin do not show extensive 
distribution of lesions. These animals are killed soon after 
infection has taken place and the lesions may be restricted 
to a single place such as a lymphatic gland or other organ. 

In other cases where the disease is of long standing old 
lesions of considerable proportion are found. For illustrations 
of the appearance of tuberculous lesions see Plates V to XXX. 



*The Federal meat inspection regulations state that animals affected 
with "extensive or generalized tuberculosis" are to be condemned. "Evi- 
dences of generalized tuberculosis are to be found in such distribution and 
number of tuberculous lesions as can be explained only upon the supposition 
of the entrance of tubercle bacilli in considerable number into the systemic 
circulation. Significant of such generalization are the presence of numerous 
uniformly distributed tubercles throughout both lungs, also tubercles in the 
spleen, kidneys, bones, joints, and sexual glands, and in the lymphatic glands 
connected with these organs and parts, or in the splenic, renal, prescapular, 
popliteal, and inguinal glands, when several of these organs and parts are 
coincidentally affected." 



CHAPTER V 

Symptoms of Tuberculosis in Cattle 

With a disease that is usually localized and slow in its 
development, the symptoms must of necessity be variable 
and often uncertain. Again, tuberculosis varies in its period 
of duration from a few weeks or months to many years. More 
than this, the disease process often becomes arrested and the 
affected tissues remain until death practically as a foreign 
body in the diseased animal. It is impossible, therefore, to 
point out any one symptom or any group of symptoms which 
will apply to all cases. 

The symptoms of chronic tuberculosis depend upon the 
location of the lesions and their extent. When they are sit- 
uated deeply and are not of great extent, they may not exhibit 
visible evidence of their presence. In such cases, the infected 
animal may present the picture of perfect health and show no 
disturbance of function. Indeed some animals, in which the 
lesions are extensive but which have never presented signs 
of the disease, are slaughtered for beef without a suspicion 
of the presence of tuberculosis until they are examined post- 
mortem. 

Since the organs affected in tuberculosis vary so much in 
different individuals, it is not possible to give a description 
of what can be designated the characteristic or even the usual 
evidence of this disease. There are, however, certain general 
manifestations that appear in most of the advanced cases, 
such as emaciation while the appetite may continue to be 
good. This is always a suspicious indication and especially 
if accompanied by cough, rough coat, and tight, harsh skin. 
Rough or loud respiratory^ sounds are suspicious, and, in 
advanced cases, it is often found that the animal groans when 
pressure is brought to bear upon the chest wall. Hard, pain- 
less swellings (enlarged lymphatic glands) beneath the skin 



30 BOVINE TUBERCULOSIS 

above the udder, in the flank, or in the throat are suspicious. 
In tuberculosis of the lungs, coughing is the most noticeable 
symptom. It is most common after feeding, drinking, or 
after rapid movement following a period of repose, but some- 
times it occurs without any apparent cause. The cough is 
usually strong, dry and frequently of a high pitch. Some- 
times it is very violent, accompanied by protrusion of the 
tongue. Auscultation reveals modified and abnormal sounds 
in the lungs such as sibilant, sonorous and mucous rales. A 
dull sound is often detected on percussion. It is also to be 
noted that this condition is of slow development and long 
duration, thus aiding one to distinguish it, in many cases, 
from bronchitis or pneumonia. 

Sometimes large tubercular masses develop on the pleura. 
In such cases the principal symptom is a friction sound that 
is heard most distinctly during inspiration. If the masses 
are large enough they give rise on percussion to a dull sound. 
In tuberculosis of the stomach and intestines, digestion is 
interfered with. This gives rise to poor appetite, frequently 
to diarrhea and som^etimes to an alternation of diarrhea and 
constipation. In tuberculosis of the peritoneum or of the 
lining of the abdominal cavity, the lymphatic glands of the 
flank are often enlarged and hard. Sometimes this condition 
can be diagnosed positively by a rectal examination and the 
discovery of the hard, nodular masses. Tuberculosis of the 
liver does not usually give rise to obvious symptoms unless 
the disease is far advanced, in which case jaundice may be 
observed. 

Where the mediastinal lymphatic glands are enlarged 
they may press upon the esophagus, causing the animal to 
bloat habitually. Chronic or habitual bloating accompanied 
by a good appetite, especially if there is shortness of breath 
and cough, is indicative of tuberculosis of the mediastinal 
lymphatic glands. Enlarged tubercular glands along the 
esophagus may press upon that organ, causing obstruction 
and preventing the escape of gases from the stomach. 



THE SYMPTOMS 31 

In animals in which the post-pharyngeal lymphatic glands 
are enlarged from tuberculosis, the breathing is harsh and 
noisy. In this condition there is sometimes difficulty in 
swallowing, and particles of chewed up food are occasionally 
expelled from the mouth, either voluntarily when it is found 
that they can not be swallowed conveniently, or by the cough- 
ing they occasion upon reaching the pharynx. These en- 
larged glands may sometimes be detected by palpation accom- 
plished by placing one hand on each side of the throat above 
the larynx and then pressing from opposite sides. 

Tuberculosis of the udder is detected by an enlargement 
and hardening of the affected glands. Usually there is no 
evidence of pain and the milk secretion ordinarily is not 
altered until the part has been diseased for some time. In 
advanced cases, instead of milk, the udder secretes a yellowish, 
cloudy and sometimes flocculent liquid. In acute, rapidly 
developing cases, there may be pain and edema of the skin. 
In nearly all cases of udder tuberculosis the supramammary 
lymphatic glands situated above the udder in the middle of 
the escutcheon are enlarged and hard. If there is doubt as 
to the character of the disease of the udder, the milk, or pos- 
sibly a piece of excised udder tissue, may be examined bac- 
teriologically. 

In tuberculosis of the brain, the animal is unsteady and 
uncertain in its movements. It lies down much of the time, 
is usually subject to occasional cramps and is apt to carry 
the head in an unusual position. Such cases are inclined to 
advance rapidly and to terminate in death following coma 
or convulsions. 

Occasionally the disease develops in the membranes of the 
spinal cord causing pressure upon the cord which results in more 
or less paralysis. 

In tuberculosis of the bones and joints, the parts are 
enlarged; there is loss of motion, pain and usually abscess 
formation followed by the discharge of a thick yellow pus. 

In tuberculosis of the uterus or ovaries and sometimes in 



32 BOVINE TUBERCULOSIS 

peritoneal tuberculosis of the cow, the subject is almost con- 
tinually in heat. In tuberculosis of the uterus, there is some- 
times a discharge of thick, yellowish material mixed with 
mucus. In tuberculosis of the testicles the organs become 
enlarged and hard. 

In general tuberculosis, many of the symptoms described 
above may occur simultaneously. 

In all advanced cases, the nutrition of the animal is inter- 
fered with and, sooner or later, the "tuberculous cachexia" 
appears. It is, in many cases, remarkable to note the extent 
of tuberculous tissues especially on the serous membranes in 
animals that are well nourished and present no external 
signs of the disease. Animals killed in prime condition by 
the butcher are sometimes found to contain extensive and 
widely distributed lesions of tuberculosis. 

The symptoms of acute miliary tuberculosis, "galloping 
consumption", are rapid loss of flesh, depression, poor appe- 
tite, cough, weakness, rapid breathing, harsh respiratory 
sounds, some elevation in temperature, increased pulse rate 
and, sometimes, enlarged lymphatic glands. The course of 
this form of tuberculosis is always rapid and terminates in 
death. Acute miliary tuberculosis occurs when large numbers 
of tubercle bacteria are discharged into the blood or lymph 
currents. They are then carried to other parts of the body, 
filtered out in the capillaries of the lungs, liver, spleen, kidneys 
and elsewhere, resulting in the development of tuberculous 
lesions in each of these localities. The lesion from which the 
infectious material entered the circulation may have been a 
comparatively small one. This form of the disease is more 
likely to appear in young animals than in adults, and is more 
common among swine than in cattle. 



CHAPTER VI 

Methods of Dissemination 

The only way an infectious disease can spread is by means 
of the germ that causes it escaping from the infected and 
gaining entrance to the body of the uninfected individual. 
This leads to a study of three essential phases in the course 
of the disease and the life history of its virus, namely: (1) 
How do the organisms escape from the body of the infected 
animal? (2) What is their fate when expelled from the diseased 
body? and (3) How do they gain entrance into the body of 
the sound or well animal? The three questions for discussion 
therefore are (1) the channels of elimination, (2) the resistance 
of the virus to external environment and (3) the channels of 

infection. 

As tuberculosis is a specific disease due to a single species 
of bacteria all questions relating to its spread must be asso- 
ciated directly with the cause. Without this cause there can 
be no tuberculosis. This excludes at once many former theories 
that poor ventilation, lack of sunlight or the presence of filth 
was often the cause of the disease and that under such con- 
ditions it might start up anew. 

Escape of the bacteria. At what time in the course of 
the disease the tubercle bacteria escape from the infected 
animal has been a subject of considerable study during the 
last few years. As the tissue changes of tuberculosis are in 
most cases localized and as it is known that ordinarily tubercle 
bacteria are not found in the body of the infected animal 
except in the diseased part, the question as to when and how 
they escape has been one that has led to many investigations. 
In the earlier work the diagnosis was often reached from 
microscopic examinations of stained and decolorized specimens. 
This was possible because it was believed that the so-called 
tubercle stain was specific. 



34 BOVINE TUBERCULOSIS 

Later investigations have shown that tubercle bacteria 
obtained from human, bovine, avian, and fish tuberculosis are 
not the only organisms that take the tubercle stain. It has been 
demonstrated that there is a large group of bacteria which 
resist the decolorizing action of mineral acids. These include 
the bacillus of leprosy, the timothy bacillus of Moeller, the 
bacillus from butter and cheese described by Rabinowitsch 
and Petri, the Smegma bacillus, and the organism of Johne's 
disease. The suggestion that comes from very recent work is 
that there are many "acid-fast" bacteria which belong to this 
great group, and which may be mistaken for tubercle bacteria 
if identified by their staining reaction only. 

The following summary of the literature on the finding of 
tubercle bacteria in milk and excreta was made by Peterson. ^ 
Anderson 2 has also given an excellent resume of the literature 
on this phase of the disease. 

A. C. Abbott and N. Gildersleeve^ have treated extensively 
of the relation between tubercle bacilli and other members of 
the acid-fast group. They find among other things, that "the 
majority of the acid-resisting bacteria may be distinguished 
from true tubercle bacilli by their inability to resist decolor- 
ization by a 30 per cent solution of nitric acid in water." They 
make a valuable comparison between the lesions caused by 
tubercle bacilli and those caused by other acid-fast forms. The 
nodules after intravenous inoculation are seen in the kidneys 
usually, sometimes in the lungs, but nowhere else. The lesion 
is localized, there being no progressive destruction of tissue, 
and tends to terminate in suppuration or organization, not 
progressive caseation. The bulletin is valuable also because 



^Peterson. Report N. Y. State Veterinary College, 1909-10, p. 65. 

^Anderson. Bulletin No. 41, U. S. Public Health and Marine Hospital 
Service. 

^Abbott, A. C, and Gildersleeve, N. The Etiological Significance of the 
Acid-Resisting Group of Bacteria, and the Evidence in favor of Their 
Botanical Relation to Bacillus Tuberculosis. Univ. of Penn. Med. Bulletin, 
June, 1902. 



METHODS OF DISSEMINATION 35 

of its complete bibliography on this particular phase of the 
subject. 

An extended comparative study of tubercle bacilli from 
man and animals was made by Mohler and Washburn of the 
Bureau of Animal Industry of the United States Department of 
Agriculture and reported in 1907 in Bulletin 96. In addition 
to the comparative study reported, in which the conclusion is 
reached that the various forms of tubercle bacteria are more 
closely related than is generally supposed, there is appended 
a resume of literature on the question of transmissibility from 
one species of animal to another and to man. 

Theobald Smith ^ examined in 1893 six cows, all of which, 
except one, showed physical signs of tuberculosis. No state- 
ment is made regarding the physical condition of this animal. 
It was found by animal inoculation that two of the six expelled 
virulent tubercle bacilli in the milk. The udders were all ap- 
parently normal. These two positive cases, however, were so 
only near the time of death or very late in the course of the 
disease. 

E. C. Schroeder^ of the United States Department of 
Agriculture has written rather extensively on this subject. He 
announces, as the result of his work, that 40 per cent or more 
of tuberculous cows expel tubercle bacilli from their bodies in 
a way dangerous to the health of other animals and persons. 
Reynolds and Beebe" have obtained results quite contrary to 
this. Of 45 tuberculous animals examined but one was found 
to be expelling virulent organisms in numbers sufficient to 
cause the death of experimental animals. Schroeder places 
considerable credence upon microscopic findings, while Rey- 
nolds and Beebe state that such findings are untrustworthy. 



^Smith, Theobald. Bur. An. Ind., U. S. Dept. of Agric, Bulletin 3, 1893, 
pp. 60-66. 

^Schroeder, E. C. The Unsuspected but Dangerously Tuberculous Cow. 
Bur. of An. Ind.. U. S. Dept. of Agric, Circ. 118. 

^Reynolds and Beebe. Dissemination of Tuberculosis. Univ. of Minn., 
Bull. 103. 



36 BOVINE TUBERCULOSIS 

B. Bang^ tested milk from the sound quarter of an udder 
otherwise tuberculous and found that it contained virulent 
tubercle bacilli. This investigator* also tested the milk of 
tuberculous cows whose udders were sound and found 16 per 
cent positive. G. Stein ^ tested the raw milk of 14 tuberculous 
cows. He found ten negative and four positive. Some of the 
udders were tuberculous. K. Hirschberger^" found that 11 
out of 20 specimens of milk from tuberculous cows contained 
tubercle bacilli as proved by animal inoculation. He found 
microscopically only one specimen to contain the organisms. 
The virulent organisms came from early, advanced and from 
normal and tuberculous udders. F. Gebhardt^^ tested the 
effect of diluting tuberculous with non-tuberculous milk. 
When dilutions greater than 1 to 50 were made the resulting 
mixture was non-pathogenic to experimental animals. He 
found the market milk of Munich from 10 different sources 
to be negative. 

H. C. Ernst ^ ^ found that 27.7 per cent of the cows whose milk 
was examined microscopically showed the presence of tubercle 
bacilli. In all 36 cows were used. He found by animal inocu- 
lation that 42.8 per cent of the cows examined were giving off 
tubercle bacilli in the milk. In this test 14 cows were used. 
Five out of 12 calves and 2 out of 5 pigs fed with similar milk 
became tuberculous. Later ^^ he modified the above results as 



^Bang, B. Deut. Zeitschr. f. Thiermed., Bd. XI, 1884, S. 45. 

^Bang, B. Experimentelle Untersuchungen iieber tuberculose Milch. 
Deut. Zeitschr. f. Thiermed., Bd. XVII, 1891, S. I. 

^Stein, G. Experimentelle Beitrage zur Infektion der Milch perlsuchtiger 
Kiihe. Inaug. Dissert., Berlin, 1884. 

i°Hirschberger, K. Experimentelle Beitrage zur Infectiositat der Milch 
tuberculoser Kuhe. Deut. Arch. f. klin. Med., Bd. XLIV, 1889, S. 400. 

i^Gebhardt, F. Experimentelle Untersuchungen iieber den Einfluss der 
Verdiinnung auf die Wirksamkeit des tuberkulosen Giftes. Virch. Arch., 
Bd. CIX, 1890, S. 127. 

i^Ernst, H. C. How far may a cow be tuberculous before her milk becomes 
dangerous as an article of food? Amer. Jour. Med.Sci.,Vol.XCVIII,1890,p.439. 

i^Emst, H. C. Article on the Infectiousness of Milk, Boston, 1895. Pub. 
by Soc. for Promoting Agriculture. 



METHODS OF DISSEMINATION 37 

follows: The milk of 36 tuberculous cows with healthy udders 
was found by animal inoculation to be tuberculous. Five out 
of 10 pigs and 8 out of 21 calves became tuberculous when fed 
with similar milk. M'Fadyean and Woodhead''' found the 
milk and juice from 14 out of 19 tuberculous udders to con- 
tain tubercle bacteria. Two out of 13 cases were positive 
when the udder was not visibly affected. A. Florentini^^ 
found three positive cases from tests of milk from tuberculous 
cows. St. Friis^'' found 14.3 per cent of mixed milk tubercu- 
lous. He found country milk^^ entirely negative. E. C. 
Schroeder^^ in an earlier paper than the one previously men- 
tioned found the milk of 1 out of 12 tuberculous cows positive. 
Kuno Obermiiller 1 * found that 38 per cent of the animals 
he injected with cream and sediment of centrifuged milk died 
of tuberculosis. A. Buege-** found two out of six specimens of 
Halle milk to contain virulent tubercle baciUi. S. Delepine^^ 
found by inoculation from 20 to 25 per cent of unmixed milks 
to be tuberculous. W. E. Hope^^ found 5.2 per cent of the 
milk samples from town dairies and 13.4 per cent from the 



'^M'Fadyean and Woodhead. On the transmission of tuberculosis, etc. 
Internat. Cong. Hyg. and Demog., 1891, Sec 2, p. 197. 

'Tlorentini A. Giornale della R. Soc. d'igiene, 1892, p. 198. (Ref. in 
Baumgarten's Jahresb., 1892, S. 698.) 

i«Friis, St. Beitrag zur Beleuchtung der Frage iieber die Ansteckungsge- 
fahr der Handelsmilch mit bezug auf die Tuberculose. Deut. Zeitschr. f. 
Thiermed., Bd. XIX, 1893, S. 115. 

"Friis, St. Fortgesetzte Untersuchungen u. s. w. Deut. Zeitschr. f. Thier- 
med., Bd. XX. 1894, S. 195. 

•^Schroeder, E. C. Further experimental observations on the presence 
of tubercle bacilli in the milk of cows. Bulletin No. 7, B. A. I., Dept. Agric, 
1894, p. 75. 

•'Obermiiller, Kuno. Ueber Tuberkelbacillenbefunde in der Marktmilch. 
Hyg. Rundsch., Bd. V, 1895, No. 19, S. 877. 

^oBuege, A. Ueber die Untersuchung der Milch auf Tuberkelbacillen. 
Inaug. Dissert., Halle, 1896. 

■='Delepine, S. Jour. Comp. Path, and Ther., Vol. X, pp. 150, 189. 

"Hope, W. E. Report of the Medical Officer of Health, Liverpool, 1897, 
on tuberculosis as affecting the milk supply of the city. 



38 BOVINE TUBERCULOSIS 

country dairies contained tubercle bacilli. A. Massone^' found 
9 per cent of the samples of market milk from Genoa tuber- 
culous. Ott^* found 11.1 per cent of market milk samples 
tuberculous. S. Delepine^'^ found no tubercle bacilli in the 
milk from cows showing no evidence of tuberculosis and 27.24 
per cent of the milk from cows showing tuberculosis contained 
virulent tubercle bacilli. He found 5.55 per cent of mixed 
town milk tuberculous and 17.6 per cent of mixed country 
milk tuberculous. Petri ^^ found that 17.5 per cent of the 
market milk of Berlin was tuberculous. Ascher" found 1 out 
of 17 specimens of market milk tuberculous. Jaeger ^^ exam- 
ined hospital milk (cows not tested). Two out of six guinea 
pigs inoculated died of tuberculosis (two died of sepsis). 
Tubercle bacilli were found in 7 out of 100 cover glass prepara- 
tions. A. A. Kanthack^^ examined the milk from 16 dairies 
and found that 9 were selling tuberculous milk. Allan Mac- 
Fadyen'° found that 22 per cent of the samples of milk sent 
in for examination were tuberculous. Ostertag^^ found that 
1 specimen out of 49 of milk from tuberculous cows which 
showed no clinical evidence of disease was tuberculous. No 
tubercle bacilli were found microscopically. Rabinowitsch 



23Massone, A. Annali d'igiene sperimentale, 1897, p. 239. (Ref. in Hyg. 
Rundsch., Bd. VIII, 1897, S. 605.) 

2^0tt. Ein weiterer Beitrag zur Milchhygiene. Zeit. f. Fleisch-und 
Milchhygiene, Bd. VIII, 1897, S. 69. 

2 6Delepine, S. Brit. Med. Jour., Vol. 2, 1898, p. 918. 

^Tetri. Zum Nachweis der Tuberkelbacillen in Butter und Milch. Arb. 
a. d. kais. Ges.-Amt., Bd. XIV, 1898, S. I. 

^^Ascher. Untersuchungungen von Butter und Milch auf Tuberkelbacillen. 
Zeit. f. Hyg., Bd. XXXII, 1899, S. 329. 

2* Jaeger. Ueber die Moglichkeit tuberkuloser Infektion des Lymph- sys- 
tems durch Milch und Milchproducte. Hyg. Rundsch., Bd. IX, 1899, S. 801. 

^'Kanthack, A. A., and Sladen, E. S. St. B. Influence of the Milk Supply 
on the Spread of Tuberculosis. Lancet, 1899, Vol. 1, p. 74. 

'"MacFadyen, Allan. Lancet. 1899, Vol. II, p. 849. 

"Ostertag. Zeit. f. Fleisch-und Milchhygiene, Bd. IX, No. 12, 1899, S. 
221. 



METHODS OF DISSEMINATION 39 

and Kempner'2 found that 71.4 per cent of tuberculous cows 
gave milk containing tubercle bacilli. Two cows out of 14 
tested had udder tuberculosis. Boyce^^ found that 6.6 per 
cent of town milk examined in 1899 contained tubercle bacilli 
while 17.4 per cent of the country milk contained tubercle 
bacilli. Rabinowitsch^^ examined eight dairies. Three of 
these were found to be selling tuberculous milk. Proskauer'* 
examined Danish and Berlin milk. Thirty-eight and five-tenths 
per cent of the samples of the former were found to be tuber- 
culous and 55.5 per cent of the latter. 

J. F. Anderson 3 ^ examining Washington market milk, 
found that of 223 samples tested 6.7 per cent contained sufficient 
tubercle bacilli to cause tuberculosis in inoculated animals. 
Ten and seven-tenths per cent of the 104 dairies examined 
were selling tuberculous milk. 

Peterson, who studied this subject experimentally for 
more than a year, came to these conclusions: 

"The findings in these experiments are significant on the 
question of the elimination of tubercle bacilli from infected 
cattle. It is recognized, however, that the number of cattle 
kept imder observation and the time covered by the exami- 
nations are not sufficient to throw light upon the question of 
elimination of tubercle bacilli during the entire course of the 
disease. The following conclusions seem to be justified: 

"The tuberculous cattle examined that were apparently 
sound but which reacted to the tuberculin test did not elimin- 
ate sufficient tubercle bacilli to cause the death of experimental 
animals when inoculated with their milk or excreta or for the 
same to be demonstrated microscopically. 

"The animals that showed marked physical signs of tuber- 



"Rabinowitsch, Lydia, and Kempner, Walter. Zeit. Hyg., Bd. XXXI, 
1899. S. 137. 

"BOyce. (Results given by Annett, Lancet, 1900, p. 160.) 
'^Rabinowitsch, Lydia. Deut. Med. Woch., Bd, XXVI, 1900, S. 416. 
»'Proskauer, Seligmann, and Croner. Zeit. Hyg., Bd. LVII. 1907, S. 173. 
^^Loc cit. 



40 BOVINE TUBERCULOSIS 

culosis eliminated tubercle bacilli in sufficient numbers to be 
detected microscopically or by animal inoculation in a large 
percentage of samples of milk and excreta taken at regular 
intervals. Single examinations of the milk or feces of these 
cases might give negative results. 

"Owing to the frequency of the occurrence of acid- fast 
bacteria in the excreta and milk of cattle, the microscopic 
examination for tubercle bacilli is not sufficient to positively 
determine their presence. 

"The mere presence in the circulating blood of virulent 
tubercle bacilli or certain other pathogenic organisms does 
not seem to be sufficient to predicate their existence in the 
milk. 

"The differentiation between tubercle bacilli and certain 
other acid-fast bacteria that frequently appear in the milk 
and feces of cattle can not be made by the known methods 
of decolorization such as acidulated-alcohol and strong solu- 
tions of nitric acid." 

In order to secure information concerning the frequency 
with which tubercle bacteria escape from occult cases of 
tuberculosis in cattle and to ascertain the extent of the imme- 
diate danger of occult cases to others, a study of the elimina- 
tion of tubercle bacteria was undertaken in this college early 
in 1907 and the work is still under way. The first examina- 
tions were restricted to single specimens of milk or feces, or 
both, from cows that had been tested with tuberculin. In some 
cases the mixed milk of the dairy was taken. As a rule the 
cows from which the specimens came were free from clinical 
evidence of disease, but in a few cases symptoms were present. 
These preliminary examinations were followed by a careful 
investigation of a series of specimens of the milk and feces 
taken at short intervals from a smaller number of reacting 
cows. 

The methods employed varied slightly with the conditions 
under which the milk was received. In all cases it was cen- 
trifugalized, and the sediment examined microscopically. 



METHODS OF DISSEMINATION 41 

Guinea pigs were inoculated in a number of cases when the 
microscopic examination suggested that possibly tubercle 
bacilli were present. In many cases the cream was also exam- 
ined. The mixed milk came from small and larger herds. The 
feces were collected after the method employed by Reynolds 
and Beebe and also those normally passed. The feces were 
examined microscopically by making properly stained cover- 
glass preparations from the surface of the normally expelled 
material, from the scrapings of the rectal mucosa, or from 
the sediment in centrifugalized specimens. Several prepara- 
tions were made and examined from each specimen. 

In the preliminary work we examined a total of one hun- 
dred and thirty-six samples of milk and thirty-six of feces. Of 
the milk samples, forty-nine were mixed and eighty-seven were 
from individual cows. Of the latter two had diseased udders. 
In all, eighty guinea pigs were inoculated. They received 
two cubic centimeters each of the sediment from the centri- 
fugalized tube. Sixteen of these were injected into the abdom- 
inal cavity, the others received the sediment subcutaneously. 
The results of these examinations were as follows: 

Of the forty-nine examinations of mixed milk, tubercle 
bacteria were found in one specimen microscopically and no 
inoculations were made. Later experience suggests that 
possibly these were acid-fast organisms other than true tuber- 
cle bacteria. It was not known to us whether or not clinical 
cases existed in the herds. Guinea pigs inoculated with the 
mixed milk from two herds developed tuberculosis. It was 
known that in these herds there were clinical cases. After 
they were removed subsequent inoculations gave negative 
results. The guinea pigs inoculated with the samples from 
the other mixed milk either died within a few days from sepsis 
or remained well until killed for examination. Thus there were 
two of the forty-nine samples that contained infecting organ- 
isms and possibly the third did also. This gives at the maxi- 
mum a little over six per cent that contained tubercle bacteria. 

Of the eighty-seven examinations of the milk from individ- 



42 BOVINE TUBERCULOSIS 

ual COWS, tubercle bacteria were not found microscopically 
or by guinea pig inoculations, except in two cases, and these 
were samples of milk from the cows whose udders were affected. 
These were the only cows that showed any clinical evidence 
of disease and at the time the specimens were taken the lesions 
in the udders were not thought to be of a tuberculous nature. 
Tubercle bacteria were present in very large numbers in the 
milk from each of these cows. They were largely outside of 
the tissue cells, lying free between the leucocytes and fat 
globules of the milk. In two specimens acid-fast or timothy 
bacilli were present in very small numbers. They were decol- 
orized with acidulated alcohol and guinea pigs inoculated from 
these samples did not develop tuberculosis. If we exclude the 
two cases in which there were udder lesions, tubercle bacteria 
were not found in any of the samples. If they were included, 
a little over two per cent of the examinations were positive. 

The thirty-six examinations of the feces failed to reveal 
the presence of tubercle bacteria either microscopically or by 
animal inoculation. One specimen contained a few acid-fast 
organisms. The guinea pigs inoculated from this specimen 
did not develop tuberculosis. 

In drawing conclusions from the results of these examina- 
tions, the fact must be kept in mind that they were not made 
from selected cases, but were made from animals in herds 
that were tested in regular work. The cows were kept under 
quite different conditions; some were in the best of sanitary 
stables and others were not. The number of examinations 
is too small to warrant any general deductions. The results 
show, however, that tubercle bacteria were not present or 
discoverable at least in the milk or feces of a considerable 
number of specimens taken from reacting and apparently 
healthy cows. If a careful physical examination had been 
made and all suspicious cases removed before the bacteriological 
examinations of the milk and feces were undertaken tubercle 
bacteria would not have been found either microscopically or 
by guinea pig inoculation. 



METHODS OF DISSEMINATION 43 

As the results mentioned above were obtained from the 
examination of material from cows in herds that were at the 
time undergoing the tuberculin test, they were not, except in 
a few cases, confirmed by further or repeated examinations. 
They were, however, of the same nature as many of the earlier 
examinations from which conclusions of a far-reaching signi- 
ficance have been drawn, and upon which certain sanitary 
regulations have been based. It is to be regretted that in the 
earlier reports of milk examination for tubercle bacteria the 
condition of the cows from which it came was not more defi- 
nitely recorded. In a few cases the statement was made that 
the udders were apparently free from disease but the possibility 
of the milk becoming infected from the feces was not so fully 
considered at that time. It is possible, therefore, that ad- 
vanced pulmonary lesions or intestinal ulcers, without udder 
infection, could have been responsible, through fecal contami- 
nation, for the bacteria found in the milk. 

The results of our single examinations were so strikingly 
uniform, in that cows with udder tuberculosis were eliminat- 
ing large numbers of tubercle bacteria with the milk and that 
cows reacting to tuberculin, but showing no physical evidence 
of the disease, were not eliminating them so far as we could 
determine, in either the milk or excreta, that it seemed very 
desirable to continue the study. It was felt that errors in 
operation or coincidence might have been responsible for the 
findings. To overcome these and to ascertain whether or not 
tubercle organisms appear from time to time in the milk or 
feces of physically sound but infected cows, it was decided to 
make a series of examinations extending over a longer period 
from a smaller number of reacting animals. 

In order to have occult cases available for frequent exam- 
inations and to have the animals kept under known conditions 
several tuberculin reacting cows were procured and placed 
on our veterinary experiment station. They were of grade 
stock and in good condition. With two exceptions these 
animals were apparently in a perfectly healthy condition, 



44 BOVINE TUBERCULOSIS 

although they gave a good tuberculin reaction. The examina- 
tions of Nos. 1 to 4 inclusive were begun early in June, 1909, 
and are still being continued on Nos. 1 to 3. The examinations 
of Nos. 6 to 12 inclusive were begun in September, 1909, and, 
with the exception of Nos. 6 and 12, are still being continued. 
Nos. 5 and 13 were clinical cases and the examinations were 
made during the latter stages of the disease only. All of the 
occult cases reacted to tuberculin in February and October, 
1910, and again in February, 1911. 

The examinations were made as frequently as it was pos- 
sible. When acid-fast bacteria were found, the preparations 
were carefully treated with acidulated alcohol or strong (33^ 
per cent) nitric acid, and one or more guinea pigs were inocu- 
lated with the material from each animal exhibiting these 
organisms. The inoculation of guinea pigs with feces is not 
altogether satisfactory owing to the considerable number of 
deaths that occur from sepsis. In this work about thirty of 
the animals died from this cause. In every case, however, 
some of the guinea pigs injected with the feces containing acid- 
fast bacteria lived and were later (four to six weeks) chloro- 
formed and carefully examined. 

In order to test further the escape of tubercle bacteria in 
the milk, the milk from each of the cows Nos. 1, 2, and 3 was 
fed to two pigs during the months of July, August, and Sep- 
tember, 1909. The pigs were examined post-mortem the last 
of October and in November without finding any evidence of 
tuberculosis. 

In m.aking these examinations the same methods were 
employed as were followed in the preceding work. The exam- 
inations were begun in July, 1909, and continued until Jan- 
uary, 1911. Thirteen animals were used in these repeated 
tests. The work will be continued on these animals until 
they exhibit physical evidence of the disease or shall have 
ceased to react to tuberculin. The accompanying table gives 
the number of examinations that were made from each animal 
and the results: 



METHODS OF DISSEMINATION 



45 



Number of Examinations made from each Animal in the Eighteen 
Months from July 1, 1909, to Dec. 31, 1910. 





o. of 
nimal. 


Microscopic Examinations. 


No 


of Animal Inoculations. 


N 
A 


No. Samples 
Examined. 


No. of Times 

Acid-Fast 

Bacteria wire 

Found in. 


Milk. 


Feces. 


Positive 
Cases. 


Nega- 
tive or 




Milk. 


Feces. 


Milk. 


Feces. 


M. 


F. 


Sepsis. 


Cow No. 

u u 

Bull " 


1 

2 

3 

4 


79 
61 
83 


89 
53 

93 
32 
14 
42 
61 
18 
61 
60 
36 
17 
4 


7 
10 
10 


32 

20 

32 

1 

8 
17 

23 

10 

15 

28 

14 

5 

4 


7 

8 
7 

11 
6 
2 

7 
1 
5 
3 



13 
3 

9 

4 
1 
8 

8 
8 
10 
1 
2 







5 








2 




20 

11 

16 




Cow " 


5' 


19 

45 
54 

Dry 
67 
26 
37 
20 

Dry 


2 
6 

7 


8 


(1 a 


62 


7 


u u 


7 


10 


a » 


8 




« » 


9' 


6 
3 

2 


1 


14 


» u 


10 












9 


u u 


11 


15 


« « 


122 


4 


u « 


131 


2 














Total, 


491 


580 


53 


209 


57 


67 


5 


3 


116 



•Cows Nos. 5 and 13 were clinical cases. 

^Cows Nos. 6 and 12 were killed in another experiment September, 1910. 

'Cow No. 9 developed a cough in October. The positive case was in a 
guinea pig inoculated in November. The cow is still under observation. 

A few examinations of the saliva have been made from each case, but 
tubercle bacteria were found in that from Nos. 5 and 13 only. 



The two clinical cases were of interest. Number 5 was an 
old cow, exhibiting symptoms of well advanced disease. She 
was very poor and the supramammary lymph gland was con- 
siderably enlarged. When received she ate well. Microscopic 
examinations of the milk and feces were made and several 
guinea pigs were inoculated. These, however, were negative. 
Later she developed a cough, when the sputum and feces were 
found to contain tubercle bacteria. The enlarged supramam- 



46 BOVINE TUBERCULOSIS 

mary lymph gland continued to increase in size and after a 
few weeks the process extended into the mammary gland itself. 
Soon after this took place the milk contained tubercle bacteria. 
This was determined by the guinea pigs that were inoculated 
with the specimens containing these organisms developing 
generalized tuberculosis. 

This cow was killed later and found to be suffering with 
generalized tuberculosis. There were old and walled-off 
lesions in the lungs, also a successive series of young and older 
miliary tubercles. About one-quarter of one mammary gland 
was tuberculous. 

Cow No. 13 was an advanced case of tuberculosis procured 
to infect a small pasture. She had a bad cough, was thin and 
not giving milk. The microscopic examination of the feces 
and expectoration showed acid-fast bacteria, presumably 
tubercle organisms. The guinea pigs inoculated with the feces 
died of sepsis, but the one inoculated with the expectoration 
died of generalized tuberculosis in thirteen days. This cow 
died before further tests were made. The autopsy showed 
advanced pulmonary lesions of tuberculosis. 

No. 4 was a young bull. He developed evidence of tuber- 
culosis and was killed in the fall of 1909. There were thirty- 
two examinations of his feces, but they did not reveal the 
presence of tubercle bacteria. The post-mortem showed lesions 
in the throat glands only. 

Number 9 was an occult case at the beginning of the work 
in 1909. In October, 1910, she developed a cough and began 
to grow thin. The guinea pigs inoculated with her milk and 
feces did not develop tuberculosis until the one inoculated 
with the feces in November. Inoculations made from the 
feces after that time gave positive results. The milk still 
remained uninfected. 

Reichel and Deubler" found in the examination of the 
feces of forty tuberculous animals that cattle with "open 

"Reichel and Deubler. An examination of the feces of forty cattle for 
tubercle bacilli and conclusions. Journal of Medical Research, XXIV, 1911, 5. 



METHODS OF DISSEMINATION 47 

lesions of tuberculosis, and throwing off tubercle bacteria in 
the feces or rectal scrapings, as a rule show physical symptoms 
of tuberculosis and are the most active disseminators of the 
disease." Further they found that "tuberculin reacting cattle 
do not necessarily throw off tubercle bacteria in the feces, 
until the development of 'open' lesions of tuberculosis, in 
which event the condition may be detected by a consideration 
of the history, careful observation and a complete physical 
examination." 

From the results of these examinations the following 
tentative conclusions were drawn: 

Cows with tuberculous udders eliminate tubercle bacteria 
with the milk. In such cases the organisms are usually 
present in large numbers. 

Cows with glandular or pulmonary tuberculosis, in which 
the lesions are discharging into the bronchi, eliminate tubercle 
bacteria with the feces and with the droolings. In cases of 
intestinal tuberculous ulcers the organisms are excreted with 
the feces. 

Milk is usually infected with tubercle bacteria when it is 
taken from cows with tuberculous udders. It may, through 
contamination with feces or uterine discharges, be infected 
when drawn from cows with open lesions in the respiratory 
tract, digestive tract, or organs of reproduction. 

Tubercle bacteria are not as a rule present in the milk of 
cows that react to tuberculin and which on a careful physical 
examination exhibit no evidence of disease. 

The number of tubercle bacteria in market milk would 
be greatly reduced, and possible entirely eliminated, by hav- 
ing frequent and thorough physical examinations of the dairy 
cows and the removal from the herd of all individuals showing 
evidence of disease. 

The fate of tubercle bacteria outside of the body. The 
fate of tubercle bacteria after they leave the body depends 
upon the surroundings into which they are cast. If they are 
expelled with the saliva and fall upon pastures where direct 



48 BOVINE TUBERCULOSIS 

sunlight reaches them they soon perish. If they are swallowed 
and appear in the fecal matter where they are more or less 
protected from sunlight and drying they will live longer. If 
they fall on mangers in dark and damp stables they will live 
for a considerable time. Efforts have been made to determine 
just how long tubercle bacteria will survive under different 
conditions but the results are somewhat contradictory and 
also incomplete. However, dark and damp stables are said 
to remain infectious for several months. 

When tubercle bacteria escape with the milk they may be 
taken by calves, pigs or children and some of them may gain 
access to the tissues. Tubercle bacteria do not ordinarily 
multiply in milk but they will remain alive and virulent in 
its products for some weeks. There are reports that they 
remain virulent for a much longer time. 

When the lesions that are discharging into the channels 
of exit such as the intestines are located in the digestive tract 
or generative organs the specific bacteria escape with the nat- 
ural discharges. From these, stables often become infected. 
The fate of the bacteria here depends largely upon the condi- 
tions relative to light and dryness. 

The channels of infection. Cattle are infected for the 
greater part through the digestive and respiratory tracts. 
There is considerable doubt in the minds of certain patholo- 
gists as to which of these modes of entrance is the more common. 
They are occasionally infected through the generative organs. 

With these general channels of infection it is not difficult 
to understand the many possible ways by which tuberculosis 
spreads. Practically, we have to consider its spread under 
two conditions, namely: (1) from one herd to another, and 
(2) from one animal to another in the same herd. 

While there are many possibilities for tubercle bacteria to 
gain entrance to any herd, the usual and practically the only 
ways by which they are introduced are (1) by bringing infected 
animals into a sound herd and (2) by feeding unsterilized 



METHODS OF DISSEMINATION 49 

separated milk or whey from creameries or cheese factories 
where the milk from tuberculous cattle is received. 

The "buying in" of the disease has been a very common 
means of infecting previously sound herds. This has been 
brought about by the purchase of animals in the various 
stages of the disease. Occasionally farmers have been care- 
less and bought "open" cases of tuberculosis. These rapidly 
spread the bacteria to other animals in the herd. The diseased 
animals may be throwing off tubercle bacteria from the lungs; 
in this case they infect the mangers, stables and perhaps 
pastures. Watering troughs also become infected with the 
saliva containing the tubercle organisms. This may remain 
on the surface of the water where a healthy animal may take 
it up. Cattle frequently "nose" each other and in various 
other ways come in direct contact. If the newly purchased 
animal is infected but is as yet a closed case, it may be weeks, 
months or even years before it spreads the virus and perhaps 
it never will. Many herds have become extensively diseased, 
however, from buying apparently healthy, but infected cattle. 
Because of the difficulty in detecting temporarily arrested 
cases, or those that are in the period of incubation, it is not 
safe to buy from herds in which the disease exists. 

Tuberculosis is spread very often through infected creamery 
and cheese factory by-products. Taking the separated milk 
from creameries where the milk from open cases of tuber- 
culosis is received to feed calves is one of the most prolific 
means of spreading the disease. RusselP** has published very 
valuable data on this subject. The infection of calves is a 
very serious matter as usually they do not show the disease 
for some time. It often becomes arrested and lies dormant 
for a variable time. No one can afford to feed calves from a 
sound herd with the separated mixed milk from a creamery 
unless he is sure the cattle in the dairies furnishing the milk 
are free from tuberculosis. 



"Russell. Bulletin No. 143, Univ. of Wis. Agric. Exp. Station, 1907. 



50 BOVINE TUBERCULOSIS 

The Spread of tuberculosis is not strange or contrary to 
the general laws that control the dissemination of pathogenic 
microorganisms. Because tuberculosis is usually localized 
and slow in its development, unexpected results are often 
encountered but they are readily explained. As we have no 
means of measuring the resistance of any animal to infection 
and as we can not determine the virulence of the germ in any 
particular case, the problem is difficult to elucidate but not 
so hard to understand if we appreciate the law of variation in 
the course of infectious disease. An active lesion may become 
arrested, or a dormant tubercle may become active and pro- 
gress rapidly to a generalized and open case of the disease. 
The laws of chance may cause an open case to infect in an in- 
credibly short time an entire herd. On the other hand very few 
animals may be infected from it. 



CHAPTER VII 

The Diagnosis of Tuberculosis in Cattle 

When the nature of tuberculosis is understood it will be 
evident that its diagnosis is not always easy. It is not difficult 
in animals where the disease is advanced but in a large per- 
centage of infected cattle the tissue changes are still so slight 
that its detection can be made by the use of certain specific 
methods only. Again it is not always possible for one to be sure 
even from very suggestive symptoms that the cause of the 
abnormal condition is tubercle bacteria. 

As tuberculosis is very common among cattle, at least in 
certain localities, symptoms such as coughing, malnutrition, 
enlarged glands in the throat or elsewhere, or trouble in the 
udder are very suspicious. There are, however, other causes 
that will give rise to such symptoms and general appearances 
and consequently a positive diagnosis can rarely be made 
from their presence. 

The positive diagnosis of a specific disease like tuberculosis 
is made by one or the other of the following methods, namely: 

1. By the character of the tissue changes. 

2. By finding the specific germ of the disease in the tissues 
or discharges. 

3. By some specific reaction such as that of tuberculin. 
The identification of tuberculosis can be made in most 

cases from the tissue changes, where the affected part can be 
removed from the animal, when they are sufficiently advanced 
and not modified by secondary infections. Microscopic exam- 
ination is of much assistance in cases where the tubercles 
are small and exhibit the somewhat characteristic cell arrange- 
ment. There are, however, cases of tuberculosis where the 
lesions are atypical and which can not be diagnosed by their 
gross or microscopic appearance. In these cases it is clear 
that some specific method of diagnosis must be applied. 



52 BOVINE TUBERCULOSIS 

From the description of the location and nature of the 
tissue changes in animals affected with tuberculosis it is clear 
that the diagnosis must be based on the lesion rather than on 
its location in the body. It is also true that most of the tissue 
changes are beneath the surface of the body so that they can not 
be removed for examination. If, however, the affected area 
can be removed from the living animal as in case of certain 
enlarged glands, or if the diseased tissues are taken from the 
dead animal, an accurate diagnosis can be made from their 
gross or microscopic appearance in a very large percentage of 
cases by one skilled in the nature of the tissue changes. 

The bacteriological examination was availed of for diag- 
nosis as soon as the tubercle bacterium was discovered. This 
consists first in finding the organism in the tissues by a micro- 
scopic examination. This has been made possible by the tuber- 
cle stain. It was thought for many years that this method 
was a means of diagnosis and that the presence of "acid- 
fast" bacteria was sufficient to make a positive diagnosis. 
More recently it has been shown that non-pathogenic "acid- 
fast" bacteria resembling tubercle bacteria very closely are 
occasionally found in excreta and more rarely in milk. This 
discovery has rendered a positive diagnosis by microscopic 
examination alone very difficult, in fact it is impossible in cer- 
tain cases especially of the excreta. Cases seem to be rare 
where the non-pathogenic forms can not be differentiated from 
tubercle bacteria by means of the decolorization with acid- 
ulated alcohol. There are some cases, however, where this 
is impossible.* Nevertheless the bacteriological method is 
of great assistance. 

In using the microscopic examination for bacteria it is 
very important to recognize that tubercle bacteria are not 
present in any excreta, or in the milk in case of udder tuber- 
culosis, until the tissue changes have advanced sufficiently 
to enable the bacteria to escape. In the examination of dead 



*Peterson {loc. cit.) found several cases of this kind. 



THE DIAGNOSIS 53 

tissue from old lesions it is often impossible to find the organ- 
isms by this method. 

Animal inoculation. A more reliable procedure is to inocu- 
late guinea pigs subcutaneously with the suspected material. I f 
it is tuberculosis the guinea pig will develop the disease and 
die of tuberculosis usually in from three to six weeks. From 
the dead guinea pig the disease can generally be determined 
from the appearance of the lesions but a microscopic examina- 
tion of the affected organs (liver, spleen or omentum) will 
usually reveal the presence of tubercle bacteria. If desired, 
cultures may be obtained from the fresh tissues. It often hap- 
pens that the presence of the bacteria can be determined by 
this method when the microscopic examination alone would 
be negative. 

Tuberculin. The most reliable means of diagnosis in the 
living animal is by the use of tuberculin. The subcutaneous 
injection is the most certain method of using it although 
other methods such as the conjunctival and intradermal use 
have certain advantages. 

The difficulty in diagnosing tuberculosis with tuberculin 
rests in two conditions: first the interpretation of the tuber- 
culin reaction when the rise of temperature is slightly above 
normal, and secondly when there is no reaction in certain 
individuals in infected herds. (See chapter VIII.) 

The positive diagnosis of tuberculosis in all infected animals 
is not an easy task. In many cases, it is impossible by any 
method known at the present time to tell whether an animal 
that has been exposed to an open case of the disease (an animal 
that is giving off tubercle bacteria) has become infected. 

There has been too much confidence in the infallibility of 
methods for diagnosis. The symptoms, the tissue changes, 
the examination for the specific bacteria and the reac- 
tion of tuberculin are all valuable and the last two may 
be considered positive when the organisms are found or when 
the tuberculin gives a recognized reaction. But when the 
specific bacteria are not found and the tuberculin does not 



54 BOVINE TUBERCULOSIS 

cause a reaction we can not be so sure that infection does not 
exist. There is a limitation to the diagnostic information that 
can be acquired by the use of any of the known methods or 
reactions used in the diagnosis of tuberculosis. 

Unfortunately for the veterinarian, the owner or the pur- 
chaser, the negative findings are not conclusive while the 
positive ones are. Experience has shown that in large herds 
when a high percentage of the animals react to tuberculin 
more or less of the others are infected. The International 
Tuberculosis Commission recommended that when 50 per 
cent of a herd reacted to tuberculin the entire herd should 
be considered tuberculous. 



CHAPTER VIII 

Tuberculin and its Use 

Tuberculin is the liquid (usually glycerinated bouillon) on 
which tubercle bacteria have grown until it has become sat- 
urated with the product of the organisms. The term tuber- 
culin seems to have first been used by Bujwid for the name of 
the preparation made from cultures of tubercle bacteria from 
which the organisms had been removed. This substance was 
first discovered by Robert Koch in 1890. It was called by 
him "lymph" and it was known as the Koch "lymph." Later 
Koch accepted the term tuberculin and applied it to his 
preparation. 

Since Koch first discovered tuberculin a number of other 
substances have been obtained from tubercle bacteria by other 
workers and given different names. Thus we have "Tuber- 
kulocidin" of Klebs and the ''New Tuberculin'' prepared by 
Koch from the bodies of the living, unheated tubercle bacteria. 
There are a large number of other preparations of tuberculin 
made by some modification of the original method. The old 
tuberculin, or Koch "lymph", is often spoken of as "TO" and 
the New Tuberculin as "TR". The first consists of the liquid 
cultures after the removal of all of the tubercle organisms and 
the second, or New Tuberculin, is composed of an aqueous 
extract of the ground or crushed bodies of the living tubercle 
bacteria themselves. 

The Koch "lymph" or tuberculin was thought when first 
discovered to possess marked therapeutic properties. There 
are many who still maintain that it is of great value in the 
treatment of certain cases of tuberculosis. 

Experiments with tuberculin as a remedy for tuberculosis 
of cattle were made by Pearson in 1892, and were reported in 
the "Proceedings of the First International Veterinary Con- 
gress of America" in October, 1893. These experiments were 



56 BOVINE TUBERCULOSIS 

made upon cows, and showed that the general effect of tuber- 
culin on a tuberculous animal was to cause the disease to 
pursue a chronic course, or, in some cases, to become latent, 
but not to disappear. 

These and other experiments with tuberculin as a pre- 
ventative and also as a cure for tuberculosis of animals were 
made during several years following Koch's discovery. It 
was at last established that while tuberculin has a specific 
effect upon the lesions of tuberculosis, and perhaps in some 
cases causes the lesions to become encapsulated, this effect 
is by no means constant, nor is it sufficiently frequent to 
render this treatment of practical value. 

The real value of tuberculin to the veterinarian and to 
the dairyman lies in its diagnostic properties. The new tuber- 
culin (TR) was believed to possess immunizing properties, 
but experience has shown that it can not be recommended for 
that purpose other than experimentally. 

The Committee of the American Public Health Associa- 
tion ^ on standard methods for the preparation of tuberculin 
recommended that the following points be observed in 
its preparation. These recommendations are followed fairly 
closely by all those who are preparing it in this country. 

"The medium shall consist of bouillon prepared from 
meat (veal or beef) and not meat extract. The bouillon shall 
contain 1% peptone (Witte's), 0.5% sodium chloride or acid 
potassium phosphate, chemically pure glycerine 5% (this may 
vary from 3 to 7%). The final reaction of the bouillon shall 
be 0.75 to 1.0 to phenolphthalein, the normal acidity of the 
broth being corrected by the addition of sodium hydrate 
solution. 

"The culture of tubercle bacterium employed shall be of 
mammalian origin and shall produce an active tuberculin. 

"The containers in which the cultures of tubercle bacteria 
are grown shall be in form similar to the Erlenmeyer flasks 



lAm. Jour. Public Hygiene, Vol. XX, No. 3, Aug. 1910. 



TUBERCULIN AND ITS USE 57 

of the Jena pattern, preferably 300 c.c. capacity, each flask to 
contain 100 c.c. of bouillon. 

"The cultures should be allowed to grow for four weeks 
after the surface of the medium is completely covered with the 
growth of the tubercle bacteria. 

"In the preparation of the tuberculin the ripe cultures are 
shaken down, placed in a steam sterilizer and subjected to live 
steam for at least 23^ hours, filtered through paper, and evapor- 
ated to one-tenth of original volume. Before being supplied to 
practitioners the tuberculin should be passed through Chamber- 
land or Berkefeld filters. 

"Tuberculin should be sent out from the laboratory so that 
the practitioner need not dilute it before using. The dilutions 
when exposed to the air should not for human practice be 
prepared for any great length of time before use. The dilutant 
suggested is 0.25% phenol in physiological normal salt 
solution." 

The technique for preparing tuberculin is as follows: The 
tubercle bacteria are grown in pure culture at a temper- 
ature of about 37.5° C. (99.5° F.) on a liquid medium con- 
sisting of beef tea containing peptone (about 1%) and glycerin 
(from 5 to 7%). In some laboratories a little acid potassium 
phosphate is added. This glycerinated peptonized bouillon 
is put in flasks. Usually from 100 to 250 c.c. are put in each 
flask. After it is sterilized it is inoculated with tubercle bac- 
teria by transferring some of the growth from a young culture 
to the surface of the liquid in the fiask. These bacteria do 
not grow in the depth of the liquid, but form a membrane over 
the surface. After the cultures have grown for a sufficient 
length of time, which varies from four to ten weeks, the flasks 
are placed in a water bath and heated to a temperature of from 
55° to 65° C. for about two hours, after which they are boiled. 
After boiling, these cultures are filtered through ordinary 
filter paper to remove the mass of bacteria. The filtrate is 
then evaporated over a water bath to the desired consistency 
and is then filtered through a porcelain or Berkefeld filter. 



58 BOVINE TUBERCULOSIS 

In some laboratories it is filtered through the porcelain filter 
before it is concentrated. See Plate III. 

The original Koch tuberculin was evaporated to one-tenth 
the volume of the culture liquid, i. e., 100 c.c. of the culture 
liquid was evaporated to 10 c.c. and a little carbolic acid 
(3/2 of 1 per cent) added to the filtrate to preserve it. It is 
kept in glass-stoppered bottles. 

It has been found that either the human or bovine variety 
of tubercle bacteria can be used in the preparation of tuber- 
culin. It has also been found that occasionally a culture of 
tubercle bacteria is obtained which will not produce a satis- 
factory tuberculin. The active principle in tuberculin is 
believed to come from the bodies of the tubercle organisms 
that have become macerated in the culture fluid. 

Application of tuberculin. Although tuberculin has been 
employed for a nimiber of years as a diagnostic agent for 
detecting tuberculosis in cattle, methods for its application 
do not seem in general to be fully understood. Although its 
application is simple in detail, it is very important that all 
the conditions attending its use should be observed. 

Tuberculin should not be applied to an animal that is 
suffering from any other infectious disease or any abnormal 
condition, giving rise to an elevation of temperature, or to an 
animal that is far advanced in pregnancy. The reason for not 
testing a cow advanced in pregnancy is because animals in 
that condition have sometimes been reported to give a rise 
of temperature following the injection, when they are not 
tuberculous. This has not been the experience of the writer. 
. The animals to be tested should be kept under perfectly 
normal conditions with the possible exception that it is nec- 
essary to keep them up in stables rather than to allow them to 
run in a pasture. Before injection, the temperature of the 
animals should be taken. It is recommended that the tem- 
perature be taken every two hours for four to six hours pre- 
ceding the injection of tuberculin. Some of the official regu- 
lations require three temperatures taken at intervals of two 



TUBERCULIN AND ITS USE 59 

hours before injection. The real purpose of taking these pre- 
liminary temperatures is to ascertain whether the animals 
have an abnormal temperature or not*. If the temperature 
is abnormal the animal should not be tested at that time. 

The tuberculin is administered subcutaneously. It is 
usually injected under the loose skin in the neck or in the 
axilla. In its application, it has been found advantageous 
to reach over the animal and apply it on the opposite side. 
Care should be taken that the syringe is sterilized. It has 
been advised that the skin of the cow at the point of injection 
should also be disinfected. This is a safe precaution; but 
the diflficulty of disinfecting the skin quickly and the infre- 
quency with which cattle become infected with skin organisms 
suggest that this precaution is not necessary. After the syringe 
is sterilized the recommendation of Dr. Law seems to be a 
good one, namely, to insert the needle in pure (liquid) carbolic 
acid between each two injections. This destroys any organ- 



*In cattle there is occasionally considerable variation in the body tem- 
perature within 24 hours. Cold water, when drunk in considerable quan- 
tities, lowers the temperature from 1 to 3°. A temporary excitement may 
cause an elevation of from 1 to 1.5°. There are often marked variations in 
the temperature of the same animal on consecutive days. The temperature 
at 12 noon and 12 midnight is often the same. In some cases the maximum 
elevation occurs near midnight, and on the following day the minimum tem- 
perature will be recorded at that time. It is not uncommon for a maximum 
temperature to occur twice a day and occasionally several times within the 
twenty-four hours. There are marked individual variations in the effect 
of ordinary conditions, such as food, excitement, and temperature of the air, 
upon the temperature of the animal. A hot spell (tempjerature 90° F.) 
may cause a rise of 2° and even 4°. The average temperature of the animals 
in three herds tested was 102.5°, 102.6° and 101° F. respectively. In 
a well-kept government herd that was tested with tuberculin the temper- 
ature of part of the animals was taken hourly for twenty-four hours preceding 
injection. An examination of the records (Bulletin No. 7, Bureau of Animal 
Industry, U. S. Department of Agriculture, Washington, D. C, 1894. The 
tests were made under the direction of Dr. Theobald Smith by Drs. F. L. 
Kilborne and E. C. Schroeder) shows the average daily variation of twenty 
of these animals to be 2.31° F. The maximum individual variation in a sin- 
gle day was 4.3° F., the mimimum 0.5° F. 



60 BOVINE TUBERCULOSIS 

isms that might become attached to the needle in withdrawing 
it from one animal, and the acid that adheres to it seems to be 
sufficient to prevent the introduction of living organisms when 
the needle is inserted into the next animal. 

The dose. The dose of tuberculin ordinarily given to an adult 
animal of mediimi size is 0.25 c.c. ofthe Koch tuberculin. The 
tuberculin from the laboratories in this country is usually 
sent out already diluted, so that 2 c.c. is the dose. The quan- 
tity to be given is almost always marked on the bottle. It 
represents as nearly as possible 0.25 c.c. of the concentrated 
Koch tuberculin. In administering it some veterinarians have 
emphasized the importance of still further diluting it, so that 
5 c.c. is injected instead of 2 c.c. The purpose of this is to 
minimize the loss of the tuberculin which necessarily adheres 
to the dish and syringe. The exact dose, i. e., the one that 
gives the best reaction, has not been determined. It has been 
stated by a few workers that a much smaller quantity will 
give a diagnostic reaction, but that the rise of temperature 
does not occur until after a much longer time has elapsed. 
When applied to young or very small animals or to very large 
ones the dose should be regulated accordingly. 

Beginning six or at the latest eight hours after the injection, 
the temperature of the animal should be taken hourly, or at 
least every two hours, for eighteen hours after the injection, 
that is, five temperatures at intervals of not more than two 
hours. If at the end of this time the temperature of any animal 
appears to be rising it should be taken again and repeated at 
like intervals until it returns to the normal. In taking tem- 
peratures it is recommended by some to lubricate the ther- 
mometers with vaseline. 

During the time that the test is being made the cattle 
should be kept quiet, free from all exposures or excitement, 
and fed and watered as usual. The water should not be too 
cold. 

Reaction. The usual reaction consists in a rise of tempera- 
ture, beginning about the sixth or eighth hour after injection 



TUBERCULIN AND ITS USE 61 

and continuing for several hours. The rise varies from 1° or 
1.5° to 4° or 5° F. above the normal. A reaction, however, does 
not mean simply a rise of temperature for a brief time, but a 
gradual rise, a continued high temperature for a few (2 to 6) 
hours and then a gradual decline. This is called the tuberculin 
curve. It is more important in the interpretation than the 
simple rise of temperature. Formerly official regulations for 
testing cattle called in case of a reaction for a certain rise of 
temperature above the highest preliminary temperature. At 
first it was thought that there should be a rise of at least 2° F. 
Later, 1.5° F. was considered a reaction. It is the writer's 
belief, after the careful examination of many tests and the 
making of many post mortems following tuberculin injection, 
that a slight rise may represent a reaction. When the max- 
imum temperature ranges from 103.5° F. down to 103° F. or 
even to a few tenths of a degree less, the cases are suspicious 
if the curve is well marked. When animals with such tem- 
peratures are slaughtered from 40 to 60% of them usually 
reveal tuberculous lesions. With our present knowledge one 
can not be positive of a reaction with a temperature curve 
having a maximum of less than 104° F. but all cases in which 
the subsequent temperature ranges between 103° and 104° F. 
should be considered suspicious. A large percentage of animals 
giving such temperatures that have been slaughtered have 
proven to be tuberculous. There are a few cattle owners who 
exclude from the herd animals that give a temperature even 
lower than 103° F. following the injection of the tuberculin 
if there is evidence of a gradual rise and decline. 

In many animals there is an organic or constitutional 
reaction which consists in roughening of the coat, evidence of 
chill, dullness of the eye, indifference to food and a general 
depressed appearance. In the writer's observation this has 
happened in a small percentage of cases. The testimony of 
others indicates that it may be more frequent. In milch cows, 
in case of reaction there is some shrinking of the milk, due 
probably to the rise of temperature. In cows that do not react 



62 BOVINE TUBERCULOSIS 

the effect upon the flow of milk is slight, if any at all. When 
the test is made in summer and the cattle are taken off from 
pasture for this purpose and fed hay, there may be some 
diminution in the milk owing to these conditions. * It is possi- 
ble that excitement may have some influence. 

How does tuberculin act? The use of tuberculin has demon- 
strated three distinct and interesting phenomena: First, a 
marked sensitiveness of the tuberculous individual and a com- 
parative indifference of the healthy body to it. Second, a 
distinct thermal reaction of the tuberculous individual, that 
is, a general effect. Third, a hyperemia of the tuberculous 
focus. These can be demonstrated in the tuberculous guinea 
pig. The extent of the hyperemia of the tuberculous focus 
in cattle does not seem to be so marked as it is in the infected 
guinea pig. The explanation for the rise of temperature in 
the tuberculous body following the injection of tuberculin is 
not easy to determine. A number of explanations have been 
offered for the action of tuberculin S but the one first suggested 
by Eber^ some twelve years ago and modified slightly by 
Theobald Smith ^ seems to meet the conditions better than any 
of the others. It is as follows: 

"in the tubercular tissues and their immediate vicinity the 
tubercle bacteria have induced certain tissue changes, and 
with them certain new functions of the tissue have been aroused 
which are the result of immunization. These new properties 



*Gilliland has made a careful study of the effect of tubercuUn on the flow 
of milk. He found it has no effect on the flow of milk from non-reactors and 
the slight shrinkage in those that react was attributed to the rise of tem- 
perature. Proceedings Am. Vet. Med. Asso., 1907. 

^Citron (Berliner klin. Wochenschrift, 1907) expresses the opinion that 
the reaction to tuberculin consists in the multiplication of sessile cell recep- 
tors and free antibodies at the focus of infection, after which the latter dis- 
appear. He states further that in the last stage of the reaction there are 
numerous fixed cell receptors and free antibodies in the tuberculous foci and 
in the serum. 

2Eber. Deutsche Zeitschrift fiir Tiermedizin, Bd. XXI, S. 34. 

'Smith. The Harvey Lectures, 1905-6, p. 272. 



TUBERCULIN AND ITS USE 63 

are concentrated in the immediate neighborhood of the focus. 
The specific resistance is, as it were, chiefly focal and only 
secondarily generalized. When the tuberculin comes in con- 
tact with the focus, the former is acted on, with the result 
that the originally innocuous tuberculin becomes poisonous 
perhaps by the splitting off of some poisonous substance. An 
incomplete digestion I should prefer to call it. As a result of 
this action we have, first, the local hyperemia and, second, 
the constitutional effect. In other words, the tubercuUn 
becomes poisonous by an immune reaction directed toward 
the tubercle bacillus. This reaction is defective and in so far 
dangerous to the host. T,he only way in which the danger 
can be met is for the body to produce an antibody to this 
second substance. So far there is little evidence to show that 
the body is abfe to produce this in any amount. The animal 
body has learned to protect itself by suppressing multiplica- 
tion rather than by attempting to neutralize such poisons."* 

The interpretation of the reaction. When a typical tuber- 
culin reaction occurs the interpretation of it is that the animal 
is suffering from a tuberculous infection and that most likely 
the process is more or less active. This reaction may occur 
when the tuberculous focus is very small, in fact, it is possible 
that it should take place when the specific lesions are still 
microscopic in size. In most post mortems, however, the 
bones, spinal cord and brain are not examined; and we know 
tuberculosis becomes localized in these organs in a certain 
number of cases. It is possible that in those individuals where 
reaction takes place and where no evidence of the disease is 
found in a gross examination of the viscera, a more careful 
examination of the organs, intermuscular and subcutaneous 
tissues, as well as of the bones and nervous system, might 
reveal the presence of macroscopic lesions. Tuberculous 
lesions have occasionally been found in bones, especially ver- 



*This secondary poison is probably of the same nature as the aggressins 
recently brought forward by Bail. 



64 



BOVINE TUBERCULOSIS 



tebrae and joints, and in the membranes covering the brain 
and spinal cord. 

In cases where there is no reaction the interpretation is 
more difficult. Formerly the assumption was that tuberculin 
will cause a reaction in all infected animals, and that if the 
animal does not react it is free from infection. But tuberculin 
does not give a reaction during the period of incubation. It 
does not give a reaction in most if not all cases where the 
disease has become arrested, encapsulated or healed.* 

It is stated on good authority that tuberculin does not 
give a reaction in certain cases where the disease is very far 
advanced. A number of veterinarians have reported cases 
of cattle that gave no reaction following the injection of tuber- 
culin, but which on slaughter and post mortem were found 
to be very extensively diseased. Dr. Wills, of the N. Y. State 



*In certain herds where the Bang method has been applied the results 
have been quite different respecting the original non-reacting animals. In 
one case where there were 17 reacting and 13 sound individuals, but one of 
the 13 subsequently reacted, although tested semi-annually for four years. 
In other herds a much larger percentage of the supposed sound animals reacted 
on subsequent tests. 

In a large herd of cattle tested there were 96 cows that did not react. 
These were placed by themselves in a practically new barn, and three months 
later, and every six months thereafter, the sound herd was tested. Those 
that responded were promptly removed and the stable was thoroughly dis- 
infected with a 5 per cent solution of carbolic acid after each test. The 
results of the consecutive tests of the non-reacting animals are exceedingly 
instructive. They are as follows: 



1904. 
1905. 

1906. 

1907. 

1908. 



July 96 tested ; 3 1 reacted, 65 did not react ; 



Jan... 
July.. 
Jan... 
July.. 
Jan... 
July.. 
Jan... 
Aug.. 



.65 
.57 
.42 
.27 
.24 
.22 
.21 
.20 



15 
15 
3 
2 
1 
1 
1 



" 57 




" 42 




" 27 




" 24 




" 22 




" 21 




" 20 




" 19 





32.2% reacted. 

12.3 

26.3 

35.7 

11.1 

8.3 

4.5 

4.7 

5.0 



During this time the non-reacting animals were kept by themselves. 
There was no opportunity for infection after they were removed from the 



TUBERCULIN AND ITS USE 65 

Department of Agriculture, has furnished me with several 
cases of this kind. The fact should not be overlooked that 
such animals are obviously diseased and would be rejected on 
physical examination. The explanation as to why certain 
very advanced cases do not react is not altogether clear. 

Limitations of tuberculin. The limitations to the action 
of tuberculin when applied to infected cattle are: (1) when the 
disease is in the period of incubation; (2) when it is arrested; 
and (3) in certain cases where the disease is very advanced. 

The records of tuberculin tested herds do not necessarily 
always point out all the animals in the herds that are infected, 
or those which may subsequently develop an active form of 
the disease. The recently infected and latent cases cannot 
be detected until the disease becomes active. To catch them 
early requires repeated tests. It is not known how long the 
lesions may lie dormant, but we have individuals where they 
sprang into activity after three and one-half years, and also a 
case where an apparently healed, calcified tubercle contained 
living virulent tubercle bacteria three years after the cow 
ceased to react. It is such cases as these that have caused 

original herd, except possibly from those that reacted from time to time. 
Several of the reactors were examined post mortem. The lesions were as 
a rule slight in extent, but of long standing. They were surrounded by a 
wall of fibrous tissue. The explanation is that these animals were infected 
while associating with the diseased cattle, some of which were eliminating 
tubercle bacteria, and that the lesions had become arrested before the first 
test was made. The repeated tests of the reacting animals in the same herd 
support this hypothesis. The second test, made three months later, showed 
fully 25 per cent not to react. Several of these continued not to respond, 
while others reacted again later. This oscillating of the morbid process 
between an active and an arrested condition is an important factor in con- 
sidering the future of the supposed healthy animals and in interpreting the 
tuberculin reaction. 

The value of tuberculin in detecting tuberculous infected cattle is indis- 
pensable in examining cows to be purchased. If they fail to react, and they 
come from infected herds, it is very necessary that the test be repeated. 
Experience has shown that when a herd becomes extensively infected (50 per 
cent or more reacting), a considerable number of the non-reactors are sufifer- 
ing from latent or dormant tuberculosis, which may become active later. 



66 BOVINE TUBERCULOSIS 

tuberculosis to reappear in many herds after the reacting 
animals have been destroyed. The owners of such herds 
are inclined to blame the tuberculin or the man who used it. 
The fault is not with the tuberculin or with the person who 
applied it, but in the failure to have subsequent tests made. 

There is great need for more investigations into the failure 
of tuberculin to react in arrested cases. It is very important 
to know about what percentage of infected cattle have the 
disease in the latent form and also to determine when in the 
process of healing the tuberculous foci will not respond to 
tuberculin. The report of Carini^ that there are about 17% 
of infected cattle that do not react seems larger than our ex- 
perience indicates. These are matters of great importance to 
take into account in the interpretation of the negative results, 
especially in cattle that are in badly infected herds. It will 
probably be demonstrated that the extent of the infection in 
the herd will be a safe guide in the estimation of the number 
of arrested or healed cases among the non-reactors. There 
seem to be no data on the frequency with which infected 
cattle recover. It is believed that such cases are more numer- 
ous than has heretofore been supposed. 

The skin and ophthalmic tests. It has often been noted, 
especially in the human subject, that a considerable degree of 
local irritation occurs at the site of the injection of tuberculin 



*Carini. Arch. wiss. u. prakt. Tierheilk, 1906, p. 562. 
The failure to recognize this fact has caused the disease to reappear in many 
herds where the reacting animals from the first test had been destroyed. 
This is illustrated from the following observation: 

In July, 1906, a dairyman purchased 92 cows from a tuberculous dis- 
trict on the tuberculin test. They were tested every six months thereafter. 
They were kept by themselves for a year, and were not exposed to known 
infected cattle after their purchase. The results of the subsequent tests 
were as follows: 

1907. Jan 92 tested; reacted. 

June 92 " 3 " 89 did not react; 3.3% reacted 

1908. Jan 89 " 24 " 65 " " " 26.9 

Aug 65 " 4 " 61 " " " 6.2 



TUBERCULIN AND ITS USE 67 

on tuberculous patients. The significance of this phenomenon 
was not fully appreciated until the investigations of von 
Pirquet^ on so-called accelerated reactions in revaccinations 
against smallpox. This condition recalled the well-known ex- 
periments of Koch which led to the discovery of tuberculin: 
namely, that in a tuberculous guinea pig a second inoculation 
under the skin was followed by much more swelling than the 
first and a rapid formation of a slough without involvement 
of the surrounding lymph nodes as in the primary infection. 
Von Pirquet's attention was directed, in consequence of this, 
to the effect of tuberculin rubbed into scarifications on the 
skin. In 360 tests in children in the Berlin and Vienna clinics 
it was found that a well-marked difference was obtained in 
the reaction hyperemia between tuberculous and non-tubercu- 
lous children under two years of age, but in older individuals 
this was slight. The diagnostic value, therefore, seemed to be 
limited to children. This method was tried by Arloing^ and 
Vallee^ in cattle, rabbits and guinea pigs, with somewhat un- 
certain reactions produced in the scarifications. 

In order to overcome the danger of injecting too much 
tuberculin in making a diagnosis on the human subject a method 
was simultaneously proposed by Calmette^ of Lille, France, 
and Wolff- Eisner^ of Berlin. The method consists in putting 
a drop of weak tuberculin solution (1%) into the eye, whereby 
a conjunctival hyperemia is produced in tuberculous individ- 
uals. This is due to the increased sensitiveness of the tissue 
of tuberculous as compared with non-tuberculous persons, 
who should exhibit no signs of irritation from the same pro- 
cedure. The recent tests of this method in the human subject 
have given a variety of results and reactions have been ob- 
tained in a considerable number of individuals who appeared 



*Von Pirquet. Berliner klin. Wochenschr., May 20, 1907. 
«Arloing. Comptes Rendu de la Soc. de Biol., June 28-29. 1907. 
bailee. Ibid., July 12, 1907. 

«Calmette. Presse Medicale, June 19 and July 13, 1907. 
"Wolff-Eisner. Berliner klin. Wochenschr., June 3, 1907. 



68 BOVINE TUBERCULOSIS 

to be perfectly healthy and who had no history of tubercu- 
lous infection. The view has been expressed that this reaction 
may take place in healed cases of tuberculosis, due to the 
fact that the conjunctiva and possibly skin have been sensi- 
tized by some previous infection, however slight. If it is dem- 
onstrated that this reaction occurs simply as the result of 
anaphylaxis it would not indicate the presence of active tuber- 
culosis. 

In this method a modified tuberculin is used* to avoid the 
irritating effect of the peptone and other foreign substances 
that are present in the bouillon from which the old tuberculin 
is prepared. 

This method of applying tuberculin has been tested in 
cattle by a number of workers, but as yet it is not generally 
considered to be satisfactory. McCampbell and White ^^ have 
published their results with it. Their procedure was as 
follows: 

'The method first tried was the administration of the tuber- 
culin as prepared by Calmette. A one per cent solution was 
made by dissolving the precipitate, obtained by treating tu- 
berculin with absolute alcohol, in sterile water. The solution 
was sterilized by steam at 100° C. One- tenth (0.1) to one-fifth 
(0.2) cubic centimeter of the above solution was placed in the 
conjunctival sac of each cow. No results were obtained by the 
use of this method. There is a possibility that the amounts 
used were too small. 

"The tuberculin which proved to give the most successful 
results was procured from the Bureau of Animal Industry, 
United States Department of Agriculture. It was used full 
strength and twenty-five hundredths (.25 c.c.)of a cubic centi- 

*This is prepared by precipitating the active principle from the old tuber- 
culin by means of alcohol, then obtaining definite solutions of ? to 1% of 
the dry powder in sterilized normal salt solution. A drop of this solution 
is put in the eye. In the human subject various strengths have been tried 
and are used. 

1 "McCampbell and White. The ophthalmo-tuberculin reaction in cattle. 
The Jour, of Experimental Medicine, Vol. X, No. 2, 1908, p. 232. 



TUBERCULIN AND ITS USE 69 

meter was placed in the conjunctival sac of each cow with a 
sterile eye dropper. The right eye was used, its condition 
being noted and compared with the left at the time of injec- 
tion. Accurate data were recorded in regard to the tempera- 
ture before and after the instillation of the tuberculin into 
the eye." 

They conclude that "the ophthalmo- tuberculin reaction 
is of some value for diagnosis of tuberculosis in cattle. A char- 
acteristic conjunctivitis with exudation coming on from six 
to eight hours, reaching a maximum in from sixteen to twenty- 
four hours disappearing in forty-eight hours, is noted in tuber- 
cular animals. It is important that the pure tuberculin should 
be used. The ordinary tuberculin which contains peptone, 
glycerin and carbolic acid should not be used." 

The reaction is said to be more pronounced in those ani- 
mals which have not been recently tested with tuberculin. 
With this reaction as with the usual tuberculin test one injec- 
tion and reaction probably inhibit a second reaction during 
a period of from six weeks to a year. The ordinary tuberculin 
test does not seem to interfere to any great extent with the oph- 
thalmo-tuberculin test at least within four weeks. The tuber- 
culin test occasionally prevents absolutely a second reaction, 
and usually no second reaction occurs within six weeks to a 
year, as before stated. There seems to be a difference in the 
results on this point. 

According to McCampbell and White cattle recently tested 
with tuberculin by the subcutaneous method react to the oph- 
thalmo-tuberculin test but the reaction is slightly reduced in 
its intensity. The ophthalmic test may possibly serve as a 
means of diagnosis of tuberculosis in cattle which have been 
tested with tuberculin by the ordinary method and will not 
react a second time, or where tuberculin has been injected into 
cattle in order that they may clear a second test. 

No constitutional disturbance has been noted in any of the 
cattle tested, that is, no rise in temperature, loss of appetite or 
falling off in the production of milk. The instillation of tuber- 



70 BOVINE TUBERCULOSIS 

culin into the eye does not seem to produce the general reaction 
which attends in some cases the subcutaneous injection of 
tuberculin. The exudate disappears leaving the eye perfectly 
normal in about forty-eight hours. 

VonPirquet and Schniirer" also tested their method on 
cattle with the following conclusions: 

"In accordance with the findings in man and with the state- 
ments of Vallee, Guerin, Lignieres and Berger for cattle, we 
can assert that the tuberculous cow, in the same manner as the 
tuberculous man, reacts to cutaneous and conjunctival intro- 
duction of tuberculin with local, characteristic inflammations 
of the skin and mucous membrane. 

"Cattle which show no fever on subcutaneous tuberculin in- 
jection also fail to react to cutaneous and conjunctival appli- 
cation of tuberculin. 

"On the other hand, tuberculous cattle may show the 
fever reaction on the injection of the usual large doses, but 
fail to show the skin and mucous reaction with the present 
available preparations. 

"The positive result of any one of the three tests shows 
tuberculosis; they are not fundamentally different, but only 
quantitatively, and in this respect the fever test is to be looked 
on as the surest, the other two as weaker but about equal in 
value. 

"For the practical method of clearing out tuberculosis from 
a herd of cattle the simplest process is to employ the con- 
junctival reaction as a discriminating reaction. In an un- 
doubted positive result the animal is to be regarded as tuber- 
culous; in a doubtful or negative case of the conjunctival test 
the subcutaneous injection should be applied." 

Lignieres and Berger ^^ modified the method of von Pirquet 
by rubbing the tuberculin upon the scraped skin rather than 
into the scarified dermis. They proposed the term cutis reaction 

^ ^VonPirquet and Schnvirer. Allergic bei Tuberkulose der Kinder. 
Monatsh. f. prakt. Tierheilkunde, Bd. XIX (1908), S. 405. 

i^Lignieres and Berger. Bull. Acad, des Sciences, Paris. 28 Oct., 1907. 



TUBERCULIN AND ITS USE 71 

for this modification and dermoreaction for the method of 
von Pirquet. 

Personally I have tried the eye reaction in a few tuber- 
culous cattle only. In these there was a slight reddening of 
the conjunctiva in a few cases, but the difference between the 
injected and non-injected eyes was not sufficient in several 
cases to warrant a diagnosis. In several animals there did not 
seem to be any visible effect. The method has the disadvant- 
age, especially in cases of a mild reaction, that the conclusion 
as to whether there is or is not a reaction depends upon the 
opinion of the observer in interpreting the appearance of the 
eyes. This reason is sufficient to cause one to hesitate to 
recommend it, especially to those who have not given the 
method careful experimental study. In using it one must 
take into account the existing conditions which might cause 
a mild or a temporary conjunctival hyperemia. The statement 
of von Pirquet and Schniirer that a negative reaction can not 
be considered conclusive and that it must be followed later 
with the subcutaneous injection suggests further that it has 
no advantage over the subcutaneous method. 

Intradermal test. Ward and Baker ^^ made a careful test 
of the intradermal method of injecting tuberculin recom- 
mended by Moussu and Mantoux.!"* It consists in injecting 
tuberculin into the skin. The reaction appears a few hours 
later as a swelling at the point of injection. Ward and Baker 
found it to be positive as shown by post mortem in 28 of 30 
cases. They recommend it for range cattle. 

This method has been tried by many workers both in this 
country and in Europe. Zschokki found it accurate in about 
85 per cent. Luckey and others in this country consider it 
equal to or better than the subcutaneous method, but we 
have not found it to be so reliable. It requires a specially 
prepared tuberculin. 



I'Ward and Baker. Proceedings Am. Vet. Med. Asso., 1910, p. 291. 
'^Moussu and Mantoux. Transactions of the Sixth International Con- 
gress on Tuberculosis, Vol. IV, part 2, p. 821. 



CHAPTER IX 

Physical Examination in Detecting Tuberculosis 

IN Cattle 

The value of the physical examination of cattle is vari- 
ously estimated by veterinarians. In this country many of 
the practitioners do not consider it of much assistance while 
in Holland and Germany for instance it is believed to be quite 
sufficient to pick out the dangerously tuberculous animals. 

If the nature of the diseased areas and their distribution 
within the body are kept in mind, it will be clear that a phy- 
sical examination of the living animal is not likely to detect 
the presence of the disease in a very large percentage of cases. 
In proportion to the number of infected cattle there are few 
in which the disease can be detected by physical signs or symp- 
toms. The usual evidence of its presence are enlarged sub- 
cutaneous lymph glands, changes in the udder and general 
poor appearance where the lungs or abdominal organs are 
considerably involved. Skill in palpation, percussion and 
auscultation will often enable one to locate the diseased area. 
Those animals which are infected and in which the diseased 
foci are still very small compose by far the larger number of 
tuberculous cattle. 

Since tuberculin has come into use as a diagnostic agent 
there has been a feeling on the part of many that it was not 
necessary to develop efificiency or skill in physical examina- 
tion. This was doubtless due to the fact that such a large 
number of tuberculous cattle can not be detected on a physical 
examination that it did not seem wise to apply it to any except 
perhaps the obviously infected. An inquiry into this phase 
of diagnosis will show that in the German schools great stress 
is laid upon the importance of physical examination. We 
have been told by certain distinguished European veterin- 
arians that "Americans do not know how to make physical 
examinations". However true the charge may have been in 



PHYSICAL EXAMINATION 73 

the past, it is certain that our teachers of veterinary medicine 
are giving this subject much more attention than formerly. 
As a result, it is possible for practitioners who have made a 
study of this subject to detect abnormal conditions in a con- 
siderable percentage of infected cattle that give the general 
appearance of being perfectly healthy. It is not possible for 
them to say that the enlarged glands, the unnatural respira- 
tory sounds or dullness on percussion are due to tuberculosis. 
The fact that something is wrong is sufficient to cause the 
animal to be separated from the other animals in the herd. 
The positive diagnosis of tuberculosis can be made only after 
the application of definite methods of procedure such as a 
bacteriological examination or the application of tuberculin. 
The physical examination is not to take the place of tuberculin 
or other definite methods in making a clinical examination.* 
Although much importance is attached to the physical 
examination, the fact must be made clear that it will detect 
but a small (3 to 5) percentage of infected cattle. This small 
percentage, however, is for both the owner of the herd and 
the consumers of the milk of the greatest importance, for it 
includes most if not all of the infected animals that are giving 
off tubercle bacteria. If a herd is examined carefully at short 
intervals, it will be possible, in most cases at least, to detect 
the animals that are developing tuberculosis before the lesions 
have become advanced sufficiently to allow the germs to 
escape from the body. This makes the physical examination 
of value so far as protecting the consumers of the milk and 
the other animals in the herd, but it does not afford any pro- 
tection to the purchaser of cattle, for the occult cases can not 
be detected by this method. The value of the method is to pro- 
tect the herd from its own infection and to allow a sound one 
to be grown up, but it does not protect the purchaser of 
cattle against buying infected animals. 



*A clinical examination includes the use of tuberculin and bacteriological 
examinations necessary to make a diagnosis. A physical examination locates 
the affected part. 



74 BOVINE TUBERCULOSIS 

The objection is raised that it requires much time of a 
skilled practitioner to make the examinations. This is true 
to a certain extent, but we should remember that we can not 
rise above natural laws but must work through them. We 
can not hasten or retard to an appreciable extent tubercu- 
lous processes. When they arrive to a certain condition the 
skilled diagnostician can detect them and not before. The 
physical examination of a herd to remove tuberculosis can 
be likened to the care of a garden. If all the weeds in sight 
are removed and as fast as the new ones appear they too are 
removed before they produce seed, until there are no more 
unsprouted seed or living roots left, there will be no more 
weeds in the garden, provided of course that no seeds are 
allowed to come in from without. The physical examination 
of cattle, if properly made, will in a like manner weed out 
the infected animals as fast as the disease comes in evidence, 
and before it has advanced sufficiently to enable its seed to 
spread. If this can be done the disease must disappear from 
the herd with the natural elimination of all the present in- 
fected cattle. 

In Germany and Holland the examination includes the 
search for tubercle bacteria in the excreta, uterine discharges 
and milk as well as the evidence of disease from a physical 
examination. 

More recently Director E. Scharr and Dr. Opalka of the 
Bacteriological Institute of the Agricultural Department for 
the province of Brandenburg made a report on the bacteri- 
ological and physical examination of tuberculosis in cattle ^ 
They emphasize the importance of the examination of the 
mucus in the lower part of the trachea and upper bronchi. 
By means of a trocar, a cotton swab is introduced into the 
lower part of the trachea and the contents collected on the 
swab which is examined bacteriologically for tubercle bac- 
teria. The success of this method in finding open cases of 

^This report was translated by A. T. Peters and published as bulletin 
No. 5, State Board of Livestock Commissioners of Illinois, 1912. 



PHYSICAL EXAMINATION 75 

pulmonary tuberculosis can be determined from their con- 
clusions which are quoted. 

"With the aid of our trocar and swab we are enabled to 
procure safely and easily sputum specimens without injury 
to the animal. 

"To obtain the most positive diagnosis the swab should 
be inoculated into guinea pigs. 

"From our experiments we conclude that open tuberculosis 
of the lungs can be detected in almost all advanced cases by 
this method and in a few cases we were able to detect it in 
the earliest stages where no clinical symptoms (such as cough, 
emaciation, etc.) were present. 

"Serous tuberculosis can not be positively ascertained by 
this method. 

"The described method is a valuable one for the detection 
of open tuberculosis in cattle. Though it would seem rational 
to destroy all tuberculous cattle, this can not be done owing 
to the fact that the percentage of slightly affected animals 
is too great and the value so enormous that the State can not 
afford to pay for them all. It is necessary for the sanitary 
officers to find a more economical method." 

This method is being tried in this country but the results 
are not yet reported. It is restricted naturally to the detection 
of open pulmonary cases only. 



CHAPTER X 

Immunization of Cattle Against Tuberculosis 

Experiments directed toward the immunization of animals 
against tuberculosis have been in progress since the discovery 
of tuberculin in 1890. The product resulting from the growth 
of the tubercle bacteriimi in the body was reported by Koch 
to have the effect of immunizing experimental animals, of 
retarding the progress of tuberculosis, and, in some cases, it 
was thought to cure laboratory animals artificially infected. 
Koch observed that when a healthy guinea pig is inoculated 
subcutaneously with a pure culture of tubercle bacteria the 
lips of the inoculation wound at first unite and adhere and 
the wound appears to heal. After from ten to fourteen days 
a hard nodule forms, which breaks and continues as an open 
ulcer until the death of the animal. But the condition is quite 
different when an already tuberculous guinea pig is inoculated. 
In such an animal the wound unites at first, as before, but no 
nodule forms, and on the second or third day the seat of in- 
oculation sloughs off, leaving a fiat, shallow ulceration which 
usually heals rapidly and permanently. Koch also found 
that dead tubercle bacteria rubbed up in water could be in- 
jected in large quantities into healthy guinea pigs without 
injury other than suppuration at the point of injection, and 
that small quantities administered to infected guinea pigs 
had the effect of prolonging the life of the animals so treated. 
It, therefore, appeared to be probable that tubercle bacteria 
contain some specific soluble substances capable of exerting 
a curative action. It was in an effort to discover this sub- 
stance that tuberculin was made. 

Spengler^ reported that he had found tuberculin to be 
capable of prolonging the life of infected guinea pigs and to 
have a decided curative effect. 



'Spengler. Memoir de la Q)ngr^s de la Tuberc. a Paris, 1898. 



IMMUNIZATION OF CATTLE 77 

Koch- came to the conclusion that it was necessary, in the 
treatment of tuberculosis, to produce not only an immunity 
to toxins, but also a bacterial immunity, and felt that he had 
seen evidence of an immunity of a degree sufficient to be of 
much value. He had observed, in acute miliary tuberculosis, 
when the bacteria are distributed throughout the entire body, 
a stage during which the organisms, formerly so numerous, 
disappear to such an extent that they can be found only with 
difficulty. It appeared, therefore, that even in these cases 
there was a sort of bacterial immunity. 

Antitoxins found in the blood of animals that have been 
treated with various toxins or tuberculins have been used to a 
large extent experimentally for the purpose of immunizing 
animals against, and treating animals infected with, tuberculo- 
sis. Maragliano^ was one of the first workers in this field. He 
obtained what he believed to be a curative serum by injecting 
toxins produced by or extracted from tubercle bacteria into 
experimental animals — i. e., dogs, asses, and horses. Living 
tubercle bacteria were not administered to the animals that 
were to produce the serum. It was shown that a serum pro- 
duced in this way had the ability to neutralize the toxic effect 
of tuberculin. In 1899 Maragliano reported, at the Tuber- 
culosis Congress in Berlin, that by means of his serum he was 
able to immunize rabbits and guinea pigs against ordinarily 
fatal doses of tubercle culture. He announced that his tuber- 
culosis antitoxic serum was produced through methodical and 
progressive injections of tuberculosis toxin. 

Burnheim, Nieman, McFarland, Patterson and deSch- 
weinitz all experimented with normal serums and those pro- 
cured from animals treated with tubercle bacteria extracts, or 
tuberculins, but with no practical success. 

Von Behring, working in the same field, found that by the 
use of tuberculin toxins a specific antitoxin could be produced 
through the use of which the resistance of an animal to tuber- 

»Koch. Deut. med. Woch., No. 14, 1897. 

^Maragliano. Berlin, klin. Wochenschrift, No. 32, 1895. . 



78 BOVINE TUBERCULOSIS 

culosis could be increased to a certain, but not to a large extent. 

The work done by all these investigators may be summed 
up by saying that it is well established that by the use of a 
tuberculosis toxin it is possible to immunize an animal against 
this toxin and to produce resistance to tuberculosis already 
existing, or to which an animal may subsequently be exposed. 
But the immunizing or curative results produced by toxins 
or by antitoxins resulting from the use of toxins, while suffi- 
cient to be definite and measurable, have not been proved 
to be sufficient to be of much practical value so far as the 
protection of healthy animals against tuberculosis is con- 
cerned. Evidently, the effect of their use is to tend to the 
production of a toxic but not a bacterial immunity. 

In 1894, de Schweinitz reported some experiments made 
by him on guinea pigs, in which these animals were inoculated 
with tubercle bacteria of human origin, cultivated about twenty 
generations upon glycerin beef broth of slightly acid reaction. 
This culture was not virulent for guinea pigs but it served to 
immunize them to such an extent that when they were after- 
ward inoculated with tuberculous material from a cow, they 
remained healthy, while control animals inoculated with 
similar material died with tuberculosis in seven weeks. 
De Schweinitz also injected very large quantities of human tuber- 
cle bacteria into cattle — subcutaneously, intravenously, and 
intraperitoneally. He found that by gradually increasing the 
dose enormous quantities could be tolerated without injury. 

M'Fadyean^ reported his experiments in the problem of 
injecting emulsions of tuberculous material and cultures from 
various sources. His conclusions are quite significant. 

"It, therefore, appears to be justifiable to conclude that, 
whatever may have been the degree of natural immunity 
possessed by these three experimental cattle, it was much 
increased by the successive intravenous inoculations to which 
they were subjected. The immunity was not absolute, but 



*M'Fadyean. Jour. Comp. Path, and Therap., Vol. XIV (1901) p. 136. 



IMMUNIZATION OF CATTLE 79 

it may be doubted whether a degree of resistance that will 
merit this term is obtainable by any method in cattle." 

The most persistent efforts to immunize cattle have been 
put forth by von Behring. He has made several reports upon 
the subject. He has endeavored to immunize animals against 
tuberculosis by the use of tuberculin, other tuberculosis toxins, 
by antitoxins, by the use of dead tubercle bacteria, tubercle 
bacteria weakened by chemical agents, and by the use of 
living cultures of low virulence (bovo vaccine). Cattle treated 
by him have been tested as to their resistance to tuberculosis by 
subcutaneous and intravenous inoculations with tuberculous 
material from cattle and with cultures of virulent tubercle 
bacteria of the bovine type. The results have not been satisfac- 
tory. The experiments by Haring in California and others have 
shown that little dependence can be placed upon the use of 
bovovaccine as a practical measure of preventing the disease. 

Pearson and Gilliland^ experimented along the lines of 
inoculating cattle with living bacteria. Their conclusions were 
encouraging. They state: "After repeated intravenous in- 
jections of cultures of tubercle bacteria from human sputum 
the resistance of young cattle to virulent tubercle organisms 
of bovine origin may be increased to such an extent that they 
are not injured by inoculation with quantities of such cultures 
that are capable of causing death or extensive infection of 
cattle not similarly protected. 

"That intravenous injections of much larger quantities 
of culture of himian sputum tubercle bacteria than are neces- 
sary to confer a high degree of resistance, or immunity, upon 
the vaccinated animals, may be administered without danger 
to that animal." 

In a personal conversation with Dr. Pearson shortly before 
his death, he assured me that while it was possible to increase 
the resistance of cattle against tuberculosis by repeated intra- 
venous inoculations, a practical method had not yet been 
devised. 



^Pearson and Gilliland. Philad. Med. Jour., Nov. 29, 1902. 



80 BOVINE TUBERCULOSIS 

Thomassen, Neufeld, Weber and Tante, Friedman, Lorenz, 
Hutyra, Albrecht, Smith, Mohler and Schroeder carried out 
investigations directed toward immunizing cattle. They all 
find it possible to establish more or less resistance to the disease. 

Haring, Sawyer and Morgan « made a careful test with 
von Behring's bovovaccine. Their results showed possibly a 
temporary resistance but not a permanent immunity. 

Following the earlier investigations with tuberculin, serums 
and vaccines there have been a number of experiments reported 
that are worthy of consideration. The papers on this sub- 
ject presented at the Ninth International Congress of Veter- 
inary Medicine held at the Hague in 1909 represent the latest 
and undoubtedly most trustworthy information on this subject. 

Eber, of Leipsic, who has studied this subject very thor- 
oughly, concludes as follows concerning preventive inocula- 
tions: 

'The receptivity of young cattle to experimental infection 
by virulent tubercle bacteria may be materially diminished 
by previous inoculation with the Koch bacillus, even of varied 
origin and virulence. 

"The immunity thus conferred is not absolute. The im- 
munized cattle will succumb from the effects of a sufficiently 
heavy dose of tuberculous virus. 

"The increase of resistance is not complete for some time 
(at least three months) after inoculation, and has entirely 
disappeared at the end of the first or second year. 

"The degree and duration of the experimental immunity 
are influenced by the individual resistance, and up to a cer- 
tain point by the quality of the vaccine used. 

"No experimental method permits one to foresee the 
manner in which the vaccinated animals will comport them- 
selves toward natural or enzootic contagion. Practice alone 
must decide the value of immunization in the struggle against 
bovine tuberculosis. Tuberculin does not positively disclose the 

*Haring, Sawyer and Morgan. Proceedings Am. Vet. Med. Asso., 1909, 
p. 252. 



IMMUNIZATION OF CATTLE 81 

existence of tuberculous centers upon animals previously 
treated by injections of living tubercle bacteria. 

"Science has not yet granted us a method of inoculation 
which permits effective struggle against tuberculosis in re- 
gions seriously infected." 

The newer researches simply shed a little light upon pre- 
ventive inoculation when combined with other prophylactic 
measures (killing animals affected with open tuberculosis, 
raising the calves on sterilized milk, plowing pastures) during 
the struggle against tuberculosis. 

In practice methods of immunization are to be preferred 
which permit of annual re-inoculations. Nevertheless, more 
exact researches must be instituted for the purpose of deter- 
mining if annual preventive inoculations are sufficient in every 
case to confer satisfactory immunity. 

It is of great importance for the future to study further the 
influence of the mode of inoculation (intravenous, subcutaneous, 
digestive) upon the quality and duration of the immunity 
acquired, keeping constantly in mind at the same time the 
various channels of entrance of natural infection (digestive or 
respiratory). 

Klimmer of Dresden, who had investigated the bovo- 
vaccine of von Behring, the vaccination with "Tauruman" 
of Koch and Schiitz, the method of Heymanns and one de- 
vised by himself, concludes that the methods of von Behring 
and of Koch and Schiitz are practically of no value in combat- 
ing this disease. His own method, which consists in vaccinat- 
ing with attenuated human tubercle bacteria, has not been 
sufficiently tested. The non- tuberculous animals are vaccinated 
twice during the first year and those that are tuberculous are 
vaccinated every three months. The following year all the 
animals are vaccinated but once. It is believed that this 
method will not be more effective than the others. 

Vallee of the Alfort Veterinary College, who has carefully 
studied the various methods proposed for vaccinating cattle, 
makes the following statements: 



82 BOVINE TUBERCULOSIS 

"Nevertheless, the inoculation of cattle by any method 
with virulent human tubercle bacteria confers an appreciable 
resistance against various methods of experimental infection 
and also against natural contagion. 

"The resistance conferred is directly proportional to the 
quantity and virulence of the bacteria injected, but however 
great their value, the immunity conferred by them does not 
persist longer than 12 to 18 months. 

"The introduction of living bacteria as a vaccine con- 
taminates the entire organism. This peculiarity necessitates 
a special guard over the animals immunized, should they be 
sent to slaughter during the six months which follow the last 
vaccination. 

"Whatever the mode chosen for introducing the vaccine, 
the resistance conferred is insufhcient to assure the complete 
resorption of the bacteria inoculated for prolonging immunity. 

"The resistance to infection by the digestive tube of the 
animal vaccinated by that method is incomparably superior to 
that acquired by animals by the intravenous method, because 
it permits the organism to obtain complete resorption of the 
virulent material inoculated. Considering the frequency of 
infection through the digestive canal in cattle, the application 
of vaccinating material through the mouth appears preferable 
to every other method. 

"Vaccination by the digestive method can not be made 
entirely free from danger of infection if one uses virulent 
bacilli of the bovine type. The use of bacilli of the human 
type of slight virulence is, therefore, preferable, as these 
furnish results comparatively equal to those of the bovine type. 

"Vaccination by way of the mouth is not easily obtained 
except upon very young subjects. 

"Vaccination by way of the mouth does not place the ani- 
mals entirely beyond the danger of infection with tuberculosis. 
It permits them to resist for more than a year contact with 
cattle which present open lesions of tuberculosis and following 
this, present no lesions beyond insignificant tubercular nodules 






IMMUNIZATION OF CATTLE 83 

in the various glands. On this account it merits systematic 
study and further practical application. 

"The resistance conferred by subcutaneous methods is 
inferior to that obtained by way of the circulation. 

"Vaccination by the use of killed bacteria has given results 
inferior to those obtained with living and virulent organisms. 

"No definite conclusion can yet be actually formulated in 
regard to the various methods of immunization under dis- 
cussion, but their systematic application will permit a deter- 
mination of their real practical value." 

As a result of the various papers and discussions at the 
Ninth International Veterinary Congress in 1909 the following 
resolutions were adopted by that body: 

"At the present time there is no vaccination which in itself 
is sufficient to combat in an efficient manner bovine tubercu- 
losis in heavily infected herds. 

"In how far it is possible to bring about a more successful 
issue of the difficult struggle against bovine tuberculosis by a 
combination of vaccination with prophylactic and hygienic 
measures must be demonstrated by new practical experiments. 

"The congress urgently requests the Governments to grant 
the means for extensive experiments to examine the methods 
of vaccination against bovine tuberculosis under the different 
conditions of agricultural practice." 

The Bureau of Animal Industry, U. S. Department of Ag- 
riculture, has carried out a number of experiments directed 
toward a practical method of immunizing cattle against tuber- 
culosis. The conclusion* reached is as follows: "The only 
conclusion to which we are entitled from this work and 
from careful study of the writings of others on the subject of 
protective inoculation against tuberculosis may be stated as 
follows: Though results have been obtained which are very 
encouraging to the investigator and which prompt him to 
strive onward with renewed vigor and hope, no system ot 



•Report, B. A. I., 1910, p. 327. 



. 



84 BOVINE TUBERCULOSIS 

bovo- vaccination has reached a stage at the present time that 
justifies its use in common practice." 

It is impossible in a work of this kind to enter into a dis- 
cussion of the theories of immunity but the fact that indi- 
viduals who have suffered an attack of tuberculosis and have 
recovered at least temporarily are not protected against a 
subsequent attack or recurrence does not argue in favor of a 
protective vaccination. Success may be attained but at 
present there seems to be no method that can be recommended 
to the cattle owner for successfully vaccinating or immunizing 
his animals against tuberculosis. 



CHAPTER XI 

The Control of Bovine Tuberculosis 

The vital question for the cattle owner is, How can tuber- 
culosis be prevented or eliminated? If I have been clear in 
pointing out the nature of tuberculosis, it is evident that the 
question of control must be solved the same as other problems 
of a biological nature. As tuberculosis appeared in cattle 
early in the history of the species, it had a long time to become 
disseminated through its natural channels of transfer and 
transportation before it encountered the hostile activities of 
preventive medicine. Yet the history of the disease shows 
that in many countries, such as Denmark and Sweden, it did 
not exist until it was introduced with infected animals in 
comparatively recent time. More than this, in countries 
where it now prevails extensively there are many uninfected 
herds. The efficiency of the natural forces to spread the 
virus has been heightened during recent years, especially 
in dairy districts, by the steady increase in cattle traffic. In- 
dividual dairymen have bought and sold cattle regardless of 
this infection, thereby introducing it into thousands of herds 
where by nature's method of dissemination the virus would 
not have gained entrance. We are at once confronted, there- 
fore, by the situation in which the natural powers for the dis- 
semination of tubercle bacteria have been and still are being 
accelerated by the habits of the dairymen. The problem of 
control is a complicated one, because the spread of the virus 
through these natural channels must be checked and the 
habits of the dairymen so adjusted that they will tend to pre- 
vent rather than enhance the spread of the specific bacteria. 
Again, the problem is complicated because the infected animals 
possess a greater or less intrinsic value. Methods for control 
should provide not only for checking the further spread of 
the virus, but also for the utilization so far as possible of the 



86 BOVINE TUBERCULOSIS 

infected individuals. The subject becomes further subdivided 
because of its sanitary significance as well as its economic 
importance. 

The economic problem is many sided. In some instanges 
whole herds are infected. These are frequently the only source 
of revenue for their owners. Large nimibers of these cattle 
are suffering with single or localized foci of the disease, which 
leave the carcass fit for food. Every year our Government 
inspectors pass for sound beef thousands of animals so af- 
fected. Again, there are many herds of cattle valuable for 
their pure blood or special strains that have been obtained 
after years of expensive effort in breeding. These have a 
value to the dairy industry that is difficult to measure. Many 
of these herds may be tuberculous. We know that some of 
them are. Of the infected individuals a very large percentage 
are but slightly diseased. However, because of this infection 
they are a menace to the healthy animals, but most of them 
still possess their essential value, the ability to breed. These 
can be segregated and their offspring procured free from the 
taint of tuberculous parasitism with which their dams are 
suffering. The Bang method, which has been successfully 
and extensively applied in Europe and in many herds in this 
country, provides for a safe and economic handling of this 
class of animals. 

The control of a disease like tuberculosis after it has 
become widely disseminated is difficult because of its insidious 
nature. The purpose is to detect the infected individuals, 
but to do this we must recognize the course of the disease in 
the animal body and the limitations of our means for detecting 
it. The mere testing of large numbers of cattle with tuber- 
culin requires much time and many men. Its application must 
be repeated to detect the cases ot active disease which are very 
likely to develop from the latent ones that escape detection 
on the first test. The men who apply the tuberculin should 
be trained and competent or the results will be untrustworthy. 
The use of tuberculin is comparatively recent and generally 



THE CONTROL 87 

not well understood. It is too sensitive a reagent to be trusted 
to the unskilled. An equitable and just disposal of the reacting 
animals must be provided for. Owners must cooperate and 
they must learn the nature of the disease and its disastrous 
effects upon the herd if allowed to continue unchecked. State 
and municipal meat inspection services are a necessary com- 
plement to afford a ready and legitimate exit for many react- 
ing animals. The whole proposition is complicated. However, 
the principle of segregation — to prevent the further spread 
of the virus — is clear, and its application is not necessarily 
difficult. If the spread of tubercle bacteria could be stopped, 
and this is possible, tuberculosis would disappear with the 
present infected individuals. Because of the great values and 
the large number of animals involved and the necessity of 
supplying a constantly increasing quantity of milk, new dairy 
methods are necessary to meet the present conditions. Dairy- 
men should raise more calves and buy fewer milch cows unless 
they can be assured of sound herds from which to purchase. 
The herd is the unit to be considered, not the individual animal. 
These are among the principles that must be worked out by 
those wishing to eradicate tuberculosis. 

The dairymen are looking to the professional men, the 
Experiment Stations, and State Colleges for a remedy. The 
procedure recommended must, if successful, take into account 
nature's methods for maintaining and disseminating tubercle bac- 
teria. If nature's methods here are objectionable or destructive 
to man's best interests, as they are in reference to many other 
conditions, then it is for the scientific investigator to ascertain 
how these natural forces may be directed so as not to infringe 
upon man's rights, or so that the agencies through which they 
operate are eliminated. The analysis of the problem shows that 
we must deal (1) with what tubercle bacteria through their 
natural channels can and will accomplish if undisturbed, 
and (2) what cattle owners are doing to enhance the normal 
means for their distribution. 

In this warfare the responsibility of the individual cattle 



88 BOVINE TUBERCULOSIS 

owners must not be overlooked. The obligation owed to the 
producers by the consumers, who are clamoring for pure milk, 
must likewise be recognized. While those charged with the 
responsibility of controlling infectious diseases are educating 
the farmer that he can not afford to have tuberculosis in his 
cattle and teaching him how to free his herd of this parasitism, 
they should instruct the consumers that a pure milk can not 
be produced at the same price that a dirty milk can be sold for. 

As the prevention of bovine tuberculosis rests almost 
entirely with the cattle owners themselves, who will be suc- 
cessful according to the extent to which they adhere to the 
knowledge of the disease itself, and as this knowledge has been 
and is being given to them in bulletins, agricultural papers, 
and lectures, the question of how long the state is going to 
compensate owners for tuberculous cattle as an aid to its 
elimination is an important one. There is developing a feel- 
ing that the state should not compensate owners for tuber- 
culous animals. In New York the compensation for such 
animals has recently been increased, but the question whether 
such a law is right is being discussed in many quarters. The 
question, why a man should be paid for a tuberculous animal 
any more than for one dead of anthrax or any other preventa- 
ble disease, is being asked repeatedly. In some states there 
is small compensation, and in others its discontinuance is 
being urged. The tendency seems to be that payment for 
such cattle from public funds is to be temporary. 

There have been several well-defined methods established 
in different countries for controlling tuberculosis in cattle. 
These may be mentioned by countries. 

America. Active measures to suppress tuberculosis in 
cattle were first undertaken in the United States and Canada. 
The American system of control consists in tuberculin testing 
dairy cattle and slaughtering the reactors. It was the first 
procedure inaugurated to eradicate the disease. It was started 
when the authorities believed that human and bovine 
tubercle bacteria were identical and when tuberculin was 



THE CONTROL 89 

thought to give a reaction in all infected animals. It started 
as an official measure and carried indemnity from the state 
for the infected animals. Such payment was justified on 
the ground of public safety and equity to the owners. With 
slight modifications the system has continued in operation 
since its introduction. Could this method have been intro- 
duced soon after the infection occurred, it would have been 
successful generally as it has been in certain localities and in 
single herds where all tuberculous cattle seem to have been 
identified and eliminated. By this a large number of herds 
have been purified and their owners enabled to keep there- 
after uninfected cattle. Unfortunately in point of time this 
method came so late that in many states there were so many 
infected animals that necessary funds could not be secured 
to test all herds and to indemnify the owners of all reacting 
cattle. Again the disease had existed for so long that there 
was such a large number of arrested cases that a single test 
would not detect all of the infected individuals. 

The official use of tuberculin has been and still is restricted 
to a small percentage of the cattle. In New York it is 
less than two per cent annually. Local boards of health and 
milk commissions have required testing of perhaps 5 to 10 per 
cent more. But even this is not sufficient to insure any great 
decrease in the number of tuberculous cattle. A very large 
part of the remaining ninety per cent are not tested. In these 
tuberculosis is continuing to spread according to its own 
methods. There is more or less private testing, but where 
the laws are too stringent dairymen themselves are not active 
in finding the disease. The health authorities and often 
consumers will not permit the reacting cows to remain in 
the milking herd, although evidence of disease cannot be 
detected except with tuberculin. At the same time milk is 
accepted from herds that have never been tested and which 
often contain spreaders of the virus, as shown by an examina- 
tion of the milk. 

A long and careful study of tuberculin has shown, as 



90 BOVINE TUBERCULOSIS 

already stated, that with a reaction there is present an active 
tuberculous infection but its failure to react does not prove 
the absence of the disease. * Experience has shown and theory 
explained that when infection exists either in the period of 
incubation or in a state of arrest tuberculin is not effective. 
These findings have answered many of the criticisms that 
have been raised against tuberculin. These are usually made 
by those lacking knowledge of when it can and when it cannot 
cause a reaction. Many of these important facts have been 
disregarded, and the system, while applied with good faith, 
has occasionally allowed infection to remain in some animals 
in the herd. In these, the disease has sooner or later devel- 
oped, and the herd has again become a center for dissemina- 
tion. For this tuberculin has been unjustly blamed and not 
infrequently the integrity of the men who used it has been 
called in question. Unfortunately in this country the use of 
tuberculin has come all too often to be considered synony- 
mous with the slaughter of a herd and not as an agent of the 
greatest value in diagnosis. 

The supposition that all reacting animals are immediately 
dangerous has been carefully investigated. Many examina- 
tions of milk, feces and saliva of infected cattle have been 
made to ascertain the extent to which open cases of tuber- 
culosis exist without giving physical evidence of the same. 
This work is now in active progress but the results already 
reported** indicate that spreaders of the virus can be detected 
in a very large percentage of cases on physical examination. 



*See Resolution 2, on tuberculin, passed by the International Commis- 
sion on the Control of Bovine Tuberculosis, in Appendix. 

**MooreandBoynton. N. Y. State Dept. Health, 29th Annual Report, 
1908. 

Moore. Report of the N. Y. State Veterinary College at Cornell University, 
1910, p. 46. 

The Elimination of Tubercle Bacteria from Infected Cattle. The Jour, 
of Med. Research, Vol. XXIV (1911), p. 517. 

Peterson. Report of the N. Y. State Veterinary College at Cornell Uni- 
versity, 1910, p. 60. 



THE CONTROL 91 

Such men as Prof. Ostertag of the German "Gesundheitsamte" 
and Dr. Poels, Director of the tuberculosis work in Holland, 
trace failure to detect "spreaders" of tubercle bacteria to a 
lack of skill on the part of the examiner. Although our system 
of testing and destroying the reactors was right from the 
viewpoint of those who introduced the law, in general its 
results do not seem to have been so satisfactory or even to 
have equalled the attainments of the methods based on a 
broader knowledge of the disease and the means for the dis- 
semination of its virus. 

In 1909 the American Veterinary Medical Association 
appointed a commission to investigate and report upon a 
method for the control of bovine tuberculosis. (See appendix 
for its report and recommendations.) This report, which 
consists of a series of resolutions and a general plan of pro- 
cedure for cattle owners, seems to meet the situation as it 
exists in this country. For this reason the report is re- 
printed as an appendix to this work. The plan there recom- 
mended seems to cover every possible condition. 

Denmark. In Denmark the method known as the "Bang 
method," in honor of Professor Bang who introduced it in 
1894, is the direct and official procedure followed. It consists 
in the government testing with tuberculin all the cattle in 
a herd when requested to do so by the owner, who agrees to 
comply with the government requirements. These consist 
in separating the reacting animals from the non-reacting ones, 
either by placing them in different stables or by putting up a 
partition in the same stable. When outside they are kept in 
separate paddocks or fields. The advanced cases and all the 

Reynolds and Beebe. Dissemination of Tuberculosis by the Manure 
of Infected Cattle. Bulletin No. 103, Agric. Exp. Sta., Univ. of Minnesota, 
1907. 

Reichel and Deubler. An Examination of the Feces of Forty Cattle for 
Tubercle Bacilli and Conclusions. Jour, of Med. Research, Vol. XXIV 
(1911) p. 5. 

Schroder. The Unsuspected but Dangerously Tuberculous Cow. Circu- 
lar 118. U. S. Bureau of Animal Industry. 1907. 



92 BOVINE TUBERCULOSIS 

COWS with udder tuberculosis are eliminated. The non-reacting 
animals are tested every six months or a year, and if any of 
them give a reaction they are placed with the reactors. The 
calves of the infected cows are removed promptly after their 
birth from their dams and fed the milk of the sound nurse 
cows or the pasteurized milk of the infected ones. As soon 
as the sound herd is of sufficient size, the reacting animals 
are eliminated and their stable thoroughly disinfected. As 
a precaution all of the separated milk at creameries is pasteur- 
ized at 80° C. before it is returned to the farm. 

The success of the Bang method in Denmark where it has 
been most extensively employed has been made possible 
because of two important conditions, viz: (1) The farmer 
is allowed to sell the milk of the reacting cows with that of 
the healthy ones, except where the local authorities object 
or where infants' or children's milk is produced. (2) The 
owners are allowed to sell the reacting animals to whom and 
where they please. This freedom of action enables cattle 
owners to eliminate undesirable animals and to keep for breed- 
ing purposes the better ones. As the milk is used and the 
cattle can be sold, the method is carried out with little loss 
to the owner, with small cost to the state and at the same 
time it protects the consumers of the milk. 

On the question of eliminating tuberculosis, Professor 
Bang states that by removing all of the udder and other clinical 
cases, the danger from the milk is minimized and, therefore, 
it is much safer than it was before the herd was tested. The 
sale of reacting cattle is not prohibited, because it would 
prevent farmers from eliminating the infected individuals 
from their herds. So long as a large percentage of the herds 
are infected, the Danish government sees no objection to 
this practice. In conversation with Prof. Bang on this sub- 
ject, he stated that in a country where tuberculosis is preva- 
lent "It is no worse to sell a cow that reacts to tuberculin 
than it is to sell one that has not been tested." He would 
not approve of this practice if most of the herds were free 



THE CONTROL 93 

or if the government assumed control of all herds and com- 
pensated the farmers for the reacting animals. 

The Bang method, modified to suit the local conditions, 
has been applied with great success in Hungary, where the 
reports show that many highly infected herds have been 
freed of the disease in from four to six years. In Norway and 
Sweden the results have been equally good. Prof. Regner ' states 
that the percentage of reacting animals among 36,149 cattle 
was, at the beginning of the application of this method, 33.6 
per cent. After a period of from two to nine years, in different 
herds, it was reduced to 4.7 per cent. 

Among the first, if not the first, to put the Bang method 
to a test in the United States was the Wisconsin Agricultural 
Experiment Station 2. They began in January, 1896, with 
16 reacting animals and 18 healthy cattle. In February, 
1899, they had 27 healthy animals all the progeny of the 
group of tuberculous cattle. Russell pointed out at the time 
that the method afforded a practical and often a most desirable 
way to replace a tuberculous herd. 

The method has been successfully applied at the Geneva 
Experiment Station ^ In October, 1901, the test of the herd 
showed 13 healthy and 17 tuberculous animals. They were 
separated and the method carried out. The station suffered 
a loss of four healthy animals in a fire, and only a small number 
of heifer calves were born; but with all these disadvantages, 
in December, 1905, the herd numbered 30 sound animals and 
six tuberculous ones. The latter were slaughtered. Of the 
six, three would have passed the Federal inspection and 
their beef value been obtained had they been disposed of in 
that manner. 



'Regner, Gustav. The suppression of tuberculosis among domesticated 
animals. Eighth International Veterinary Congress, Budapest, Sept., 1905. 

^Russell, H. L. The history of a tuberculous herd of cows. Wis. Agr. 
Exp. Sta., Bull. 78, 1899. 

'Harding, H. A., Smith, Geo. A., and Moore, V. A. The Bang method 
of controlling tuberculosis, with an illustration of its application. Bulletin 
No. 277, N. Y. Agr. Exp. Sta.. Geneva, N. Y., 18%. 



94 BOVINE TUBERCULOSIS 

The same process has been followed by a number of cattle 
owners with most gratifying results. The Hon. W. E. Ed- 
wards, of Rockland, Ontario, Canada, used it in the handling 
of his valuable herd. In 1903, at the meeting of the Ameri- 
can Veterinary Medical Association, he read a most forceful 
paper ^ on his experience with the method, a few lines of which 
I quote: "The question arises, can tuberculosis, one of the 
most constant diseases present in our animals, be eradicated? 
My answer is, yes, most emphatically. I am fully convinced 
of the reasonable possibility of the eradication of tuberculosis 
from our herds and of the maintenance of sound herds." 

The method is being applied most successfully by a number 
of cattle owners in New York State. 

The Danish method requires from three to ten years to 
build up a sound herd from an infected one. The further 
and most important lesson to be taught by it is that the owner 
himself becomes educated in the nature of the disease, so 
that thereafter he will keep his herd free. Such men will not 
purchase reacting animals. The dairymen are learning that 
it is necessary to raise their own cows or to buy them from 
sound herds. 

I saw a number of herds both large and small where this 
method was being or had been carried out. It was quite as 
effective in the small as in the large herds. The Bang method 
is generally considered by cattle owners in Denmark to be 
entirely satisfactory, and if carefully applied to give the desired 
results. The increased profits accruing to those who have 
sound herds are tending to bring more and more farmers to 
apply the method. If a farmer who applies for assistance 
refuses to comply with the government demands, the request 
is denied. Certain veterinarians have organized clubs among 
cattle owners for the purpose of hastening the application 
of the method to all infected herds. 

In Denmark the government gives compensation for cases 

^Edwards, Hon. W. E. The Bang system for the eradication of tubercu- 
losis in cattle. Proceedings of the Am. Vet. Med. Asso., 1903, p. 124. 



THE CONTROL 95 

of udder tuberculosis only. Professor Bang would like to have 
compensation given for cases of open tuberculosis of the lungs, 
intestines and uterus as well as of the udder. 

While in this country, as stated above, the Bang method 
has been frequently applied with perfect success, it is con- 
sidered by many as impractical. 

England. In England there has not been up to the present 
much direct official effort to control bovine tuberculosis. In 
many places the milk is more or less regularly examined for 
tubercle bacteria, and if they are found each of the animals 
in the herds from which the milk came is carefully examined 
physically, and the milk of all the cows that are found to be 
suspicious is examined bacteriologically. If tubercle bacteria 
are found, the animal is slaughtered at once or, more usually, 
fattened and killed under inspection for beef. Under the 
new regulations, tuberculin can be used with the consent 
of the owner or his agent, but not otherwise. 

The procedure which is known as the Manchester method 
consists in taking milk from the dealers and examining it at 
regular intervals for tubercle bacteria. Professor Delepine's 
technique consists, in addition to such microscopic examina- 
tions as may be made, of the inoculation of small guinea pigs 
subcutaneously on the inside of the thigh with the sediment 
of centrifuged milk and killing them about twenty-one days 
later for examination. If tuberculosis is found the examina- 
tion extends to the individual cows in the herd from which 
the infected milk came. Professor Hubert Boyce of Liverpool 
stated that by this method they had reduced the infected 
milk supply in that city to 6 per cent. 

There is no restriction on the sale of reacting cows, and 
ordinarily the milk from the reactors and non-reactors is 
mixed and sold, except where children's milk is being pro- 
duced. The Bang method is being applied to some extent 
by private owners, but generally it does not seem to be favor- 
ably considered. There is no country where the feeling is 
stronger that bovine tuberculosis is of great sanitary signifi- 



96 BOVINE TUBERCULOSIS 

cance than in Great Britain. There seems to be no other 
where so Httle direct effort has been put forth to eliminate 
this disease from cattle. The general examination of the 
milk for tubercle bacteria has, however, done much indirectly 
to lessen the number of clinical cases of tuberculosis in the 
herds of the country. 

Germany. In Germany the method of separating the 
sound from the reacting animals as followed in Denmark is 
not looked upon with favor, largely because of the difficulty 
in separating the two classes. The law did not provide for 
compensation to the owners of cattle, although an act recently 
passed provides for the condemnation with compensation 
for open cases of lung, intestinal, uterine and udder tuberculosis. 
There are, however, in the different provinces local regulations, 
and some of these provide for a small compensation in certain 
cases. 

The method which, for some time, has received most atten- 
tion is that proposed by Dr. Ostertag. It consists in eliminat- 
ing by slaughter all clinical cases of tuberculosis, removing 
the calves promptly after their birth from their dams and 
keeping them separated for some months, after which they 
may be placed with the other cattle. During this early period 
the calves are to be fed on the milk of sound cows or on the 
pasteurized (heated to 85° C.) milk of the infected ones. It 
is considered somewhat safer to prolong the separation until 
a sound herd is built up. When cattle owners desire to do so, 
they have their herds tested with tuberculin, but as a rule 
they do not separate the reactors from the others. The herds 
are examined frequently by skilled veterinarians and all the 
animals that exhibit symptoms of tuberculosis are immediately 
eliminated either by isolation or slaughter. In this way it is 
believed that the disease will be kept in check and eventually 
the infected animals will disappear. Ostertag thinks that 
tuberculosis can be eradicated by promptly removing the 
clinical cases, with the simultaneous raising of young cattle 
free from infection. The Ostertag method is based on the 



THE CONTROL 97 

theory that the cHnical cases are so largely the spreaders of 
the virus that the few occult cases which eliminate tubercle 
bacteria may be considered as a negligible quantity. In this 
country, the Ostertag method is generally considered to be the 
treatment of the entire existing herd as a tuberculous one, 
and the building up of a new and sound herd from the offspring. 

Holland. In Holland, by Royal decree the government 
gives facilities for the official inspection of cattle destined for 
exportation. Further, by a decree of the Queen, any cattle 
owner can present animals to be examined by a government 
inspector if they are accompanied by a certificate from a 
veterinarian that the animal or animals are suffering from 
tuberculosis. If the diagnosis is tuberculosis, the animals 
are slaughtered and if they pass the inspection their carcasses 
are sold for food. If the government veterinarian is not sure 
of the diagnosis on physical examination he employs tuberculin. 
In all cases when the animals presented are found to be 
tuberculous, all of the cattle in the herd from which they 
came are inspected. If the veterinarian is in doubt regarding 
the diagnosis, the animals are tested with tuberculin. If 
tubercle bacteria are found in the mucus from the lungs or 
uterus or in the milk, the cow is killed. 

At present cattle belonging to breeders only are killed and 
compensated for by the government. 

Professor Poels thinks that tuberculosis of cattle must be 
combated slowly. He believes that the only way is to kill off 
the animals suffering with evident tuberculosis. Bang's 
method is not favored, in fact it was stated that it was im- 
possible. Professor Poels also lays great emphasis upon 
physical examination as a means of detecting tuberculosis. 
He emphasizes the importance of greater skill in clinical exam- 
ination. With Professor Bang he finds many cases of uterine 
tuberculosis and places much stress upon the bacteriological 
examination of uterine discharges. 

Professor Poels, like Dr. Ostertag, believes that reacting 
cows in the absence of physical symptoms rarely disseminate 



98 BOVINE TUBERCULOSIS 

tubercle bacteria. It is not an unusual practice to feed the 
calves the mixed milk from the reactors and non-reactors, 
and later test them with tuberculin and slaughter, under 
inspection, for food all that react. The infection under such 
conditions is so rare that the loss is of less importance than 
the extra work of feeding the calves on sound milk or pasteur- 
ized milk from infected cows. 

The practice in all of the countries mentioned, except 
the United States, of using the milk, except for infants and 
children, from tuberculin reacting cows that do not exhibit 
symptoms, and the freedom in selling such animals, make it 
possible for dairymen who desire to do so to clean up their 
herds without great financial loss and at the same time encour- 
age them to do so. The experience in Europe tends very 
strongly to the issue whether in the government control of 
tuberculosis cases of infection not recognizable on physical 
examination should be included in so far as compulsion of 
action is concerned. In Germany the clinical cases only are 
reported. The lesson from the experience in Denmark is that 
in order to keep herds free from tuberculosis the owner must 
be educated in the nature of the disease and that until he is 
thus educated there is little hope of securing herds permanently 
free from the disease. The essential lesson of the Bang and 
Ostertag methods lies in the fact that when a herd is purified 
the owner has become so thoroughly versed in the nature of 
the disease that he is able thereafter to keep his animals free 
from it. Methods for the control of tuberculosis can not be 
too radical so long as the disease is widespread. Its eradica- 
tion will be brought about through a process of eliminating 
the animals that are active in disseminating the virus and 
those that are developing lesions that in the near future will 
give off the bacteria. In addition to the exclusion of all ani- 
mals exhibiting evidence of the disease, all those that are 
infected, as determined by tuberculin test, should be excluded 
as soon as sound animals are grown up to replace them. 

The method to be followed by any individual who has an 



THE CONTROL 99 

infected herd must be determined by the existing conditions 
and to a certain extent the wishes of the owner. If the owner 
is anxious to eradicate the disease quickly the best plan seems 
to be to test with tuberculin and eliminate the reactors. The 
testing should be repeated every six months so long as any 
reactors are found and annually thereafter. The cattle should 
be given a physical examination frequently in order to detect 
advancing cases that occasionally appear between the times 
of applying tuberculin. 

If the herd consists of valuable animals the method chosen 
should tend to the conservation of the animals by following 
a more conservative procedure. If the herd is extensively 
infected, or for any other reason an owner can not afford or 
does not care to exterminate the disease as quickly as it is 
possible to do so, he can follow the German or Danish method 
and in a few years have with the going out of the old cattle 
a young and healthy herd to take its place. In any case, all 
animals showing evidence of tuberculosis should be promptly 
removed from the herd. The one point to keep in mind is that 
tubercle bacteria must not be allowed to escape from any 
infected individual. This can be prevented by removing from 
the herd every animal as soon as it gives any evidence what- 
ever of being infected. It is important that they are removed 
before the lesions become open and the bacteria escape. 

DISINFECTION 

One of the most important factors to be considered in 
the eradication of tuberculosis is the thorough disinfection 
of the stable from which open cases of tuberculous cattle have 
been removed. There is much confusion in the literature on 
the disinfection for tuberculosis. Various methods have been 
employed and many germicidal substances or disinfectants 
have been used. 

In disinfecting stables, it is essential, before applying the 
disinfectant, to remove all litter, which should be burned or 
thoroughly soaked with the disinfectant, and secondly, the 



100 BOVINE TUBERCULOSIS 

floors and walls should be thoroughly cleaned to insure its 
free access. The thorough scrubbing of the manger, gutter 
and walls with a hot soda solution will increase the efficiency 
of the disinfectant. All cracks and crevices are to be soaked 
to the bottom with the disinfectant, if a liquid is used, 
and if a gas is chosen they should be thoroughly cleaned 
to enable its free access. In the application of disinfectants 
it is necessary to understand the disinfecting power of the 
agent used with reference to tubercle bacteria. Experience 
has shown that there is apparently considerable variation in 
the resisting power of these organisms under different con- 
ditions. 

In the choice of a disinfectant, several factors are to be 
considered. 

First, in regard to the disinfectant itself. It is important 
to choose an agent that is stable and uniform in its action 
such for example as acids, alcohols or stable chemicals such 
as corrosive sublimate. Certain of the compounds of sub- 
stances in themselves valuable are found sometimes not to 
be uniform in their action. However, the cresols and certain 
of their compounds are highly recommended. 

Second, the effect upon the substance to be disinfected. 
Some agents are not satisfactory in the disinfection of sub- 
stances containing organic matter. Again, chemicals that are 
in themselves poisonous in small quantities should not be 
used in the disinfection of mangers unless they are thoroughly 
cleansed after the disinfection is completed. 

Third, facility of use and cost. A further choice of the 
germicidal agent lies in the facility with which it can be applied 
and its cost. In the disinfection of stables, one must employ 
solutions stronger than the minimum strength found to be 
effective especially on young cultures of the organism. 

For the disinfection of stables, the germicides that are 
used in solution are more satisfactory than the gases such as 
formaldehyde with steam, because ordinarily it is impossible to 
tightly seal the space. In applying disinfectants it is necessary 



THE CONTROL 101 

to use either a broom or brush with which the floor, manger, 
gutter and walls are actually scrubbed with the solution of 
the disinfectant or to employ a spray which is accomplished 
by the use of some of the spray pumps now on the market. 
For the disinfection of yards or fences around paddocks the 
"cyclone burner" attached to the end of a long iron tube 
with a wooden shield can be used to burn over the surface. 
This, however, because of the danger of fire, can not be 
recommended for general use. 

The more commonly used disinfectants are bichloride of 
mercury, carbolic acid (phenol), sulphur, calcium compounds, 
formalin and the cresols. Formaldehyde is usually employed 
in the gaseous form. For stable disinfection this is usually 
impractical owing to the difficulty of sealing up the windows 
and cracks. There are, however, many other preparations 
that are used. 

Bichloride of mercury or corrosive sublimate is a very 
good disinfectant in solution of 1 part to 1000 parts of water. 
It has, however, the disadvantage of being very poisonous 
and consequently can not be used without the greatest care. 
It has the advantage of being very inexpensive and when it 
can be intelligently applied with a brush or broom and the 
mangers and walls carefully washed after the disinfecting 
solution has dried, it can be used. Carbolic acid or phenol 
in 5% solution is also very destructive to tubercle bacteria. 
This may be applied by means of a broom or brush or with 
a spray pump. It has the disadvantage of being somewhat 
expensive. 

Liquid formaldehyde, that is, 5% solution of formalin 
in water, can be applied directly. It is a very efficient dis- 
infectant, being considered better than a 5% solution of car- 
bolic acid, and it is much cheaper. It has the disadvantage 
of being very irritating to the mucous membrane of the eyes 
and nose and is therefore disagreeable to use. It is frequently 
applied with a spray. 

In Farmers' Bulletin No. 345, issued by the U. S. Depart- 



102 BOVINE TUBERCULOSIS 

ment of Agriculture, on Some Common Disinfectants, Dr. 
Dorset has recommended in addition to the disinfectants 
mentioned, crude carbolic acid, cresol, a compound solution 
of cresol known in the U. S. Pharmacopoea as liquor cresolis 
compositus and chlorinated lime. 

One of the disinfectants early recommended for stable 
disinfection was a solution of equal parts (one-half gallon) 
of crude sulphuric acid and crude carbolic acid. 

These two substances should be mixed in wooden tubs 
or glass vessels. The sulphuric acid is very slowly added to 
the carbolic acid. During the mixing a large amount of heat 
is developed. The disinfecting power is heightened if the 
amount of heat is kept down by placing the tub or demijohn 
containing the carbolic acid in cold water, while the sulphuric 
acid is being added. The resulting mixture is added to water 
in the ratio of 1 to 20. One gallon of mixed acid will thus 
furnish 20 gallons of a strong disinfecting solution having a 
slightly milky appearance. The mixture should be applied 
to the walls and floors of the stables, saturating them with it. 

McClintic^ gives a list of a considerable number of disin- 
fectants, largely manufactured products, which have been 
tested and compared with carbolic acid. The following are 
included in that list. They are all reported to be somewhat 
stronger than carbolic acid. Carbolene, which is used 1 part 
to 100 parts of water. Chloro-naptholeum, which is used in 
from 1 to 2 parts in 100 parts of water. Creolin-Pearson is 
used in from 2 to 3 parts in 100 of water. Creso is used in 
solutions of from 2 to 3 parts to 100 of water. Lysol should 
be used in a strength of from 2 to 3 parts to 100 parts of water. 
Chlorinated lime used in solution of 5 oz. chlorinated lime to 
a gallon of water is very effective, but it possesses the disad- 
van tage of leaving a strong chlorine odor. Milk of lime and 
even lime water possess considerable disinfecting power. 



^McClintic. Bulletin No. 82, Public Health and Marine Hospital Ser- 
vice, Washington, 1912. 



THE CONTROL 103 

In disinfecting stables, it is well to use germicides that do 
not possess too much of an odor that may be absorbed by 
the milk thereby modifying its flavor. 

It should be remembered that drying and direct sunlight 
are both destructive to tubercle bacteria. They will, how- 
ever, live for a considerable time on dry mangers. This is 
especially true when they are protected by a thin coat of 
mucus as is usually the case when they come from the mouth. 

If the stables are much dilapidated, it is exceedingly diffi- 
cult to thoroughly disinfect them. In such cases it is generally 
cheaper to put in new floors and mangers. Wherever open 
cases of tuberculosis have been housed, thorough disinfection 
is important. 

NECESSITY OF A STATE MEAT INSPECTION SERVICE IN CON- 
NECTION WITH THE CONTROL OF TUBERCULOSIS 

One of the advantages in the control of tuberculosis 
over most if not all other infectious diseases is that 
the flesh of the infected animals is suitable for human 
food if the disease is still localized. This makes it possi- 
ble for the carcass of a cow reacting to tuberculin or one 
which has an enlarged gland or a slight cough and which 
is in good flesh to still retain its beef value. When the examina- 
tion reveals an enlarged gland, an area of dullness in a lung 
or any other indication suspicious of tuberculosis the owner 
can, if there is a proper inspection, have the animal slaughtered 
for beef and if she passes, recover her meat value. In many 
instances with grade herds this is a good percentage of what 
she is worth as a milk producer. At present if the salvage 
is to be saved the infected cattle have to be shipped to some 
abattoir having Federal inspection or they are killed without 
official examination. In the first instance the expense pro- 
hibits in most cases the securing of such inspection and in the 
second place, little protection is guaranteed to the consumer 
of the flesh if it is inspected by the butcher only. If there 
were a systematic meat inspection service, cattle owners 



104 BOVINE TUBERCULOSIS 

could, with perfect safety to the public, dispose of all suspi- 
cious cases for beef. The practice that has been in vogue of 
slaughtering reacting animals and not utilizing their flesh when 
fit for food has been an unnecessary if not unwarranted waste. 
The large number of tuberculous animals found by our federal 
inspectors and the considerable number of infected cattle 
that are, because of the localized condition of the lesions, 
passed for food point to the economic importance of having 
a similar protection for those who kill home grown animals. 
Unless some equitable provision is made whereby owners of 
reacting and suspicious cattle can utilize them so far as it is 
safe to do so, just so much more difficult will it be to eradi- 
cate tuberculosis from cattle. 



Tuberculosis has gradually grown into many herds of 
dairy cattle. It should be guided in such a way that it will 
grow out. The secret of accomplishing this is to prevent the 
spread of tubercle bacteria from the present infected cattle 
so that with the disappearance of the animals now infected 
this destructive disease will be no more. It is well to keep in 
mind the words of the great Pasteur, "It is within the power 
of man to eliminate the infectious diseases from the face of the 
earth". 



APPENDIX 

Report of the International Commission on the 
Control of Bovine Tuberculosis* 

To the President of the American Veterinary Medical Association: 

Owing to the great economic and sanitary significance of 
animal tuberculosis to the live stock industry of America, and 
the many and varied factors which must of necessity be 
accounted with in formulating successful measures for its 
eradication, the American Veterinary Medical Association, 
at its meeting in Chicago in September, 1909, appointed the 
International Commission on the Control of Bovine Tuber- 
culosis. The Commission was instructed to study the problem 
of tuberculosis among cattle and to report at the next meeting 
of the Association upon reasonable and economically prac- 
ticable methods or systems to be recommended to both officials 
and live stock owners for eradicating this great scourge of 
domesticated animals. 

It is recognized that tuberculosis is widely prevalent among 
cattle and other animals and that the frequency with which 
this great evil occurs is increasing rather than declining. As 
tuberculosis is one of the strictly preventable infections, there 
is good ground for the belief that through the formulation and 
enforcement of proper regulations the disease may eventually 
be entirely suppressed. 



*The Members were: Dr. J. G. Rutherford, Ottawa, Canada, Chairman; 
Dr. M. H. Reynolds, St. Paul, Minn., Secretary; Senator W. C. Edwards, 
Ottawa, Canada; Mr. J. J. Ferguson, Chicago, 111.; Mr. J. W. Flavelle, 
Toronto, Can. ; Hon. W. D. Hoard, Fort Atkinson, Wis. ; Dr. C. A. Hodg- 
etts, Toronto, Can.; Dr. J. N. Hurty, Indianapolis, Ind.; Dr. J. R. Mohler. 
Washington, D. C; Dr. V. A. Moore, Ithaca, N. Y.; Dr. M. P. Ravenel, 
Madison, Wis.; Dr. E. C. Schroeder, Washington, D. C; Mr. T. W. Tom- 
linson, Denver, Col.; Dr. F. Torrance, Winnepeg, Can 



106 BOVINE TUBERCULOSIS 

The Commission has held four meetings as follows: — 
Buffalo, New York, December 13 and 14, 1909; Detroit, Mich- 
igan, March 1 and 2, 1910; Ottawa, Canada, May 19, 20 and 
21, 1910; Madison, Wisconsin, June 27 and 28, 1910; all of 
which were well attended, very few of the members having 
on any occasion been absent. The Commission begs to pre- 
sent as a result of its labors the following report which, although 
brief, will, on examination, be found to comprise the principal 
points essential to the promulgation of a comprehensive and 
practical policy, such as may reasonably be adopted by any 
governmental body interested in the control of bovine tuber- 
culosis. 

It is quite unnecessary in view of the extensive knowledge 
already possessed by all who are familiar with the efforts which 
have hitherto been made to secure control of bovine tubercu- 
losis, to dwell at any length upon the importance of the subject 
or upon the conditions which led to the formation of the 
Commission. 

In view of the personnel of the Commission as selected by 
the American Veterinary Medical Association, and of the fact 
that so much information on the subject has been made avail- 
able through the work of similar bodies in other countries, and 
the researches of scientific and practical men in America and 
elsewhere, the Commission has not deemed it necessary to take 
any evidence either from expert witnesses or others. 

The members fully understood that the purpose which 
their appointment was intended to serve was less the acquisi- 
tion of new knowledge regarding bovine tuberculosis, than 
the careful study of the knowledge already available, and of 
the thoughts and opinions of those most entitled to speak 
with authority on the subject. 

The conclusions reached in this report are, therefore, simply 
the outcome of an earnest and thoughtful consideration of the 
various modern aspects and phases of the problem, with the 
object of crystallizing public opinion and so clearing the way 
for legislative action. 



APPENDIX 107 

They realized also that they could deal with fundamental 
principles only, and that the details of any policy which they 
might outline, must in each case, be worked out by the duly 
authorized and responsible representatives of the community 
immediately concerned. 

They nevertheless deemed it essential to study closely the 
history of the various efforts hitherto made by such countries 
throughout the world as have attempted to legislate on the 
subject. 

This naturally led to the gradual elimination of all methods 
other than such as might reasonably be adopted by any com- 
munity desiring, in the full light of present day knowledge, to 
undertake the control of bovine tuberculosis. 

It was felt, in view of the prevalence of the disease, espec- 
ially in some localities and among certain classes of cattle, the 
difficulty of providing a sufficient number of trained officials 
and the large economic questions involved, to say nothing of 
the enormous expenditure, that it would be unwise for the 
present at least, to seriously discuss a policy of universal 
compulsory testing and slaughter. 

Such a policy might perhaps be adopted with advantage 
by a small community, or one in which the disease existed to 
a very limited extent, but speaking generally, especially in 
view of past experiences in this line, it was thought better to 
omit it entirely from the recommendations of the Commission. 

All other methods of dealing with bovine tuberculosis which 
have been recommended or tried in various communities, were 
thoroughly discussed, with the object of discarding weak points 
and adopting such features as might be deemed worthy of a 
place in the official findings of the Commission. 

Every phase of the subject was in this way fully and freely 
considered, it being thought best to cover the whole ground as 
completely as possible before coming to a definite decision on 
any one point. 

In order to still further minimize the risk of omitting from 
the deliberations of the Commission any phase of the question, 



108 BOVINE TUBERCULOSIS 

four committees were appointed at the first meeting to deal 
respectively with: — 

(1) Education and legislation, 

(2) Location of tuberculosis, 

(3) Dissemination, 

(4) Disposition of tuberculous animals. 

The appointment of these committees proved to be of the 
greatest possible value in concentrating the energies of the 
various members on those branches of the subject with which 
they were most familiar, and their reports presented at sub- 
sequent meetings enabled the Commission to reach satisfactory 
conclusions much more rapidly than would otherwise have 
been the case. 

As a means of furnishing information as to the reasons for 
these conclusions and the manner in which they were reached, 
the Commission would recommend that the reports of the 
committees should be published as an appendix to this report. 

The Commission recognizing after careful study that the 
tuberculin test is the fundamental factor in any policy having 
for its object the control of bovine tuberculosis, decided that 
a pronouncement to that effect should properly occupy a fore- 
most place. 

Based on the information contained in the reports of its 
Committees and on such other information as was brought 
out in the general discussions of the Commission, the following 
resolutions were adopted for presentation to the American 
Veterinary Medical Association. 

RESOLUTION L DISSEMINATION 

As a general policy to be observed all contact between 
tuberculous and healthy cattle and between healthy cattle 
and stables, cars, etc., which may contain living tubercle bacilli 
should be prevented. To accomplish this the following specific 
recommendations are made: — 

1. There should be no sale or exchange of animals affected 



APPENDIX 109 

with tuberculosis except for immediate slaughter or for breed- 
ing purposes under official supervision. 

2. That the managements of live stock shows should 
give preference to cattle known to be free from tuberculosis, 
either by providing special classes for such cattle or in some 
other practical way, and should also take every precaution to 
prevent contact between such animals and those not known 
to be free from disease. 

3. All live stock shippers should take every precaution to 
see that cars furnished are thoroughly cleansed and disin- 
fected before use. 

RESOLUTION 2. TUBERCULIN TEST 

1. That tuberculin, properly used, is an accurate and 
reliable diagnostic agent for the detection of active tuber- 
culosis, 

2. That tuberculin may not produce a reaction under the 
following conditions: — 

(a) When the disease is in a period of incubation. 

(b) When the progress of the disease is arrested. 

(c) When the disease is extensively generalized. 

The last condition is relatively rare and may usually be 
detected by physical examination. 

3. On account of the period of incubation and the fact 
that arrested cases may sooner or later become active, all 
exposed animals should be retested at intervals of six months 
to one year. 

4. That the tuberculin test should not be applied to any 
animal having a temperature higher than normal. 

5. That any animal having given one distinct reaction 
to tuberculin should thereafter be regarded as tuberculous. 

6. That the subcutaneous injection of tuberculin is the 
only method of using tuberculin for the detection of tuber- 
culosis in cattle which can be recommended at the present time. 

7. That tuberculin has no injurious effect on healthy cattle. 



no BOVINE TUBERCULOSIS 

RESOLUTION 3. EVIDENCE FROM TUBERCULIN TEST 

That a positive reaction to tuberculin in any properly- 
conducted test, official or otherwise, in any animal in any herd, 
shall be considered evidence sufficient upon which to declare the 
herd to be infected. 

RESOLUTION 4. COMPULSORY NOTIFICATION 

That this Commission recommends the passage of legis- 
lation providing for the compulsory notification by owners 
and by veterinarians of the existence of tuberculosis in a herd, 
whether such existence be made known by detection of clinical 
cases or by the tuberculin test. 

RESOLUTION 5. LOCATION THROUGH SLAUGHTER 

This Commission recognizes that the discovery of tuber- 
culosis in animals slaughtered for food purposes furnishes one 
of the best possible means of locating the disease on the farm, 
and therefore, recommends the adoption of some system of 
marking, for purposes of identification, all cattle three years 
old and over, shipped for slaughter. 

As tuberculosis of hogs is almost invariably due to bovine 
infection this recommendation should also be made to apply 
to hogs of any age shipped for slaughter. 

It is further recommended that the discovery of tuber- 
culosis in animals coming under government inspection should 
be used whenever identification is possible, as a means of locat- 
ing infected herds and premises. All such cases should be 
reported to the proper authorities for control action. 

RESOLUTION 6. DISPOSITION OF TUBERCULOUS ANIMALS 
THE COMMISSION PLAN 

1. As a general policy in the eradication of tuberculosis the 
separation of healthy and diseased animals, and the construc- 
tion of a healthy herd are recommended. 

In order to accomplish this, the following recommenda- 
tions are made: — 



APPENDIX 111 

(1) If the herd is found to be extensively infected, as 
shown by the tuberculin test or clinical examination, even the 
apparently healthy animals in it should be regarded with 
suspicion, until they have been separated from the reacting 
animals for at least three months. 

If after the expiration of this time they do not react to 
the tuberculin test, they may be considered healthy and dealt 
with accordingly. 

It is recommended that a herd extensively infected should 
not be treated by the method of general separation, but that 
the constructicn of a new herd from the offspring only is ad- 
visable. 

(2) If the herd is found, by either or both of the above 
methods, to contain a relatively small proportion of diseased 
animals separation of the diseased animals from the healthy 
animals, and the construction of a sound herd from the healthy 
animals, and the offspring of both, is advocated. 

As a working basis in carrying out these principles, we 
advise. 

(a) That herds containing fifty per cent or more of dis- 
eased animals be treated as coming under section one. 

(b) That herds containing under fifteen per cent of dis- 
eased animals be treated as coming under section two. 

(c) That herds falling between these figures be graded 
according to the option of the owner. 

(d) That it shall be the prerogative of the owner to reject 
either plan and have his herd dealt with by removal and 
slaughter of diseased animals, with or without compensation, 
according to the public policy in operation. 

2. That when by any means the officials properly charged 
with the control of tuberculosis become aware of its existence 
in a herd to which a policy of slaughter and compensation can- 
not reasonably be applied, such herd must be dealt with by the 
owner, under government supervision, on the principle of the 
separation of all sound animals from those affected. Such 



112 BOVINE TUBERCULOSIS 

separation must be effected by treating the whole herd as 
diseased, and rearing the calves separately, either on pasteur- 
ized milk or the milk of healthy cows, or when the number of 
those affected is so small as to warrant such a course, by the 
application to the whole herd, from time to time, under official 
supervision, of the tuberculin test, and the entire segregation 
of all animals found to react. 

In the event of any owner refusing or neglecting to adopt 
either of the above methods, his entire herd to be closely quar- 
antined, and sales therefrom to be entirely prohibited. 

3. That a policy of compensation be recommended as 
useful and usually necessary as a temporary measure. 

4. That, when slaughter is necessary, in order to avoid 
economic loss, every effort should be made to utilize as far as 
possible the meat of such animals as may be found fit for food 
on being slaughtered under competent inspection. 

5. The details of the Commission Plan will be found fully 
set forth in the Appendix to this report. 

RESOLUTION 7. PREVENTION 

1. That, with the object of preventing the spread of in- 
fection, persons buying cattle for breeding purposes or milk 
production should, except when such purchases are made from 
disease free herds which have been tested by a properly qualified 
person, purchase only subject to the tuberculin test. In order 
to assist in the proper carrying out of this suggestion, the Com- 
mission recommends that official authorities should adopt 
such Regulations as will prevent the entry to their respective 
territories of cattle for breeding purposes or milk production 
unless accompanied by satisfactory tuberculin test charts. 

2. That all milk and milk by-products used as food should 
be properly pasteurized unless from cows known to be free from 
tuberculosis. 

RESOLUTION 8. CONTROL OF TUBERCULIN TEST 

That this Commission recommends the passage of legis- 
lation which will prevent the sale, distribution or use of tuber- 



APPENDIX 113 

culin by any person other than those acting with the full knowl- 
edge, or under the direction, of official authorities. 

RESOLUTION 9. EDUCATION 

As a clear knowledge of the cause and character of tuber- 
culosis among animals, the modes of dissemination, its signifi- 
cance as an economic and as a public health problem, underlie 
an intelligent adherence to the principles that must be ob- 
served in all efforts for eradication, as well as the establishment 
of proper cooperation in the great work between physicians, 
veterinarians, live stock owners, legislators, and the public 
generally, it is recommended that a widespread campaign of 
education be undertaken. To accomplish this end it is recom- 
mended that first of all a simple pamphlet on bovine tuber- 
culosis be written, in which the language used shall be of such 
character that every person of average intelligence shall be 
able to read it without being mystified by technical terms or 
phrases. This pamphlet should be published with the endorse- 
ment of the American Veterinary Medical Association and the 
special endorsement and consequent authority of the Inter- 
national Commission on Bovine Tuberculosis Control. 

RESOLUTION 10. PUBLICITY 

In concluding its work the Commission desires to especially 
appeal to the press, metropolitan, agricultural and local, to join 
in the work of extending as much as possible among the people 
the conclusions here arrived at. The vital importance of the 
life of farm animals to the welfare of all classes of society needs 
no argument in its support. The aim and sole purpose which 
has actuated this Commission has been to arrive at the sound- 
est conclusions possible in the light of the best knowledge ob- 
tainable. 

RESOLUTION 11. LEGISLATION 

It is recommended that legislation regarding the control 
and eradication of tuberculosis among domestic animals be 
made uniform ; that the laws of the United States and Canada 



114 BOVINE TUBERCULOSIS 

and other American countries for the admission into America 
of animals from without be made stringent and as much aUke 
as possible; and that the laws governing the interstate and 
inter-provincial movement of cattle and that between different 
American countries be harmonized. 

The laws governing inter-state and inter-provincial move- 
ment of cattle should be of such character that every state and 
every province will be free in its eradication work from un- 
necessary difficulties due to the existence of the disease in other 
states and provinces. 

Legislation is especially required to prevent the various 
frauds which interfere with the satisfactory use of tuberculin 
as a diagnostic agent for tuberculosis, as well as for official 
supervision over all tuberculin sold to be used by veterinarians 
and others. 

RESOLUTION 12. SANITATION 

In the eradication of tuberculosis it should be kept in mind 
that, in addition to protecting animals against exposure to 
tubercle bacteria, it is desirable to make them as resistant to 
infection as possible. This can be done by stabling them in 
clean disinfected and properly ventilated and lighted barns, 
giving them abundant clean water and nutritious food, a suffi- 
cient amount of daily exercise in the open air, and attending 
generally to those conditions which are well known to con- 
tribute to the health of animals. 

The daily removal of manure from stables, and water tight 
floors and good drainage in stables are urgently recommended. 

Young stock particularly should be raised as hardy as pos- 
sible and should be accustomed to liberal exercise and living 
in the open. 

RESOLUTION 13. IMMUNIZATION 

That as none of the various methods for the immunization 
of animals against tuberculosis have passed sufficiently beyond 
the experimental stage the Commission is unable to endorse 
any of these for practical use at the present time. 



APPENDIX 115 

RESOLUTION 14. ANIMAL TUBERCULOSIS AND PUBLIC HEALTH 

While the members recognize that the subject with which 
this Commission is primarily intended to deal is the control 
and eradication of tuberculosis among animals as an economic 
problem they cannot feel satisfied without declaring their recog- 
nition of the fact that tuberculosis among animals is also an 
important public health problem. Considered as such, the 
eradication of tuberculosis among animals should have the ap- 
proval and support of all those persons who are interested in 
curtailing human suffering and prolonging human life. 

RESOLUTION 15. GENERAL STATEMENT 

The members of the Commission wish to be clearly under- 
stood that they recognize the limitations of a report necessarily 
based on actual and not on theoretical conditions. They fully 
realize that in the event of the policy of which their recom- 
mendations form the framework, being anywhere adopted 
even in its entirety, much greater benefit will be derived, at 
least for some time, from its educative than from its executive 
features. 

The control to say nothing of the eradication of bovine 
tuberculosis, is impossible of achievement, without the hearty 
cooperation of all the men who are actually engaged in the cattle 
industry. In order to secure this cooperation, it will doubt- 
less be necessary, in most communities, to carry on an active 
and prolonged educational campaign. 

It is apparent that in the dissemination of practical and 
reliable information regarding the disease, it will be possible 
to employ a very large variety of methods. Many of these 
methods, such as bulletins, lectures and actual demonstrations 
of disease, having already been found valuable, will doubtless 
continue to be largely used. 

It must not be forgotten however, that in this, as in any 
other educative process, a measure of disciplinary control is 
essential to success. 

Needless to say such control can be secured only by the 



116 BOVINE TUBERCULOSIS 

passage of legislation which, while clear and comprehensive 
must, at the same time, be sufficiently conservative to avoid 
exciting alarm or arousing antagonism on the part of owners 
especially of valuable herds. 

The best law ever framed can be made an utter failure by 
stupid or injudicious administration, while, on the other hand, 
the most drastic legislation can be rendered acceptable if en- 
forced with reasonable tact and diplomacy. 

Provided therefore, that these qualities, combined with 
integrity, thoroughness, and determination, are available for 
administrative purposes, the members of the Commission are 
convinced that the enforcement of a law based on their recom- 
mendations, will prove to be by far the most powerful and 
effective educational agency which could possibly be employed. 

In concluding its Report the Commission would suggest 
that the Association should make such provision as may be 
necessary to carry on the work either by continuing the Com- 
mission as at present constituted or with such changes in the 
personnel as may be considered desirable. 

REPORT OF THE COMMITTEE ON EDUCATION AND LEGISLATION 

The Subcommittee on Education respectfully submit the 
following: — 

Bovine tuberculosis has become widely distributed through- 
out the United States and Canada and it has been determined 
that efficient systems or methods for its eradication and pre- 
vention either under the supervision of the state or nation or 
by the cattle owners themselves are of necessity based on a 
knowledge of the nature of the disease and its means of dis- 
semination. 

Experience has shown that the principles of eradication 
and prevention may be successfully applied by individual 
owners of infected cattle, independent of state assistance. 

Such individual aid is essential in conjunction with state or 
national assistance in the prompt eradication of the disease 



APPENDIX 117 

from infected herds and the prevention of its entry to non- 
infected herds. 

Therefore it is the sense of this committee that every pos- 
sible means should be employed for educating the cattle owners 
and the general public concerning the nature of tuberculosis; 
the care and precautions necessary to prevent its entrance 
into herds already free from the disease; and in methods for 
its eradication from herds where it now exists. 

Further, this committee approves of the following methods 
for instructing laymen, practicing veterinarians, practitioners 
of human medicine and health officers in the nature and control 
of bovine tuberculosis, namely: 

1. By the publication in agricultural and dairy papers 
of short accurately and carefully prepared articles on bovine 
tuberculosis. 

2. By publication of appropriate articles on bovine tuber- 
culosis in veterinary, medical and sanitary papers and journals. 

3. By recommending to agricultural societies, granges 
and directors of farmers' institutes and unions and especially 
those interested in creameries and cheese factories that lectures 
on bovine tuberculosis, its nature and control, be made a part 
of their programs and that so far as practicable, demonstra- 
tions be held. 

4. That those having in charge the arrangement of town, 
county and state fairs be requested to provide lectures on 
bovine tuberculosis, and if practicable to hold public demon- 
strations, at their annual meetings. 

5. By placing a copy of the report of the commission in 
the hands of the deans or directors of all veterinary and medi- 
cal colleges and schools of sanitary science in the United States 
and Canada with recommendations that special emphasis be 
placed in their courses of instruction on the nature of bovine 
tuberculosis and methods for its control. 

6. That a pamphlet dealing with the nature of bovine 
tuberculosis and methods for its control should be written in 
language intelligible to the layman. This pamphlet should 



118 BOVINE TUBERCULOSIS 

have the approval of this commission and the endorsement 
of the American Veterinary Medical Association. It should 
be published for free distribution. 

7. That Departments of Agriculture, state veterinarians, 
live stock sanitary boards and others interested in the official 
control of bovine tuberculosis be requested to promote as 
much as possible the educational features of their work, with 
the object of obtaining more support and cooperation from 
cattle owners. 

The methods suggested for carrying out an educational 
propaganda are not to be considered at the exclusion of any 
and all other ways by which the public may become informed 
on the nature of bovine tuberculosis, its great economic im- 
portance and the necessity for an intelligent and united effort 
on the part of cattle owners and those having charge of the 
control of animal diseases to eradicate this great scourge. 

The Committee is of the opinion, from the history of the 
legislation regarding bovine tuberculosis in those states and 
countries which have attempted to deal radically with the 
problem, as well as from the special information which has 
been furnished by this committee to its members, and the light 
thrown upon the subject in the discussions at its several meet- 
ings, that in order to avoid friction and failure, all important 
legislation with reference to tuberculosis must be prepared 
with due consideration for the condition of public sentiment 
and information on this subject. That tuberculosis control 
work should be developed in a progressive way. That tuber- 
culin tests made at a distance for public recognition (for 
example, in other states or foreign countries) can only be done 
satisfactorily by official veterinarians. That the Delepine 
or Manchester plan of tuberculosis free areas gradually ex- 
tended seems worthy of cautious trial. 

(Signed) M. H. Reynolds, Chairman. 
W. D. Hoard. 
J. G. Rutherford. 



APPENDIX 119 

GOV. hoard's report 

EDUCATIONAL MEANS FOR THE SUPPRESSION AND CONTROL 
OF BOVINE TUBERCULOSIS 

Mr. President and Gentlemen of the Commission: 

I place a high value on the work this Commission may do 
if performed wisely, in shaping the conviction and purpose 
of the people of Canada and the United States concerning 
the prevention and control of bovine tuberculosis. 

As yet, that conviction is but little more than an ill defined 
dread of something not clearly understood by the great mass 
of farmers. Added to this dread is a hope stronger yet, that 
the evil is not as great as has been asserted; that it is a scare 
that will soon pass over. As yet, in the minds of farmers and 
breeders generally, especially in those localities where dem- 
onstration work has not been had, there is a strong under 
current of conviction that all this talk about the disease is 
an interested plea of the veterinarians, that the trouble does 
not amount to much if the doctors and editors would hold 
their tongues and pens. 

Just as long as this bank of fog exists, it will control all 
legislation and individual effort, to get rid of the difficulty. 
At the bottom of the matter is a wide spread ignorance 
on the part of farmers as to the danger that threatens them; 
it is difficult to arouse them out of their conservation, for as 
yet, all they know about it is talk. 

The conservatism of intelligence is vastly different from 
that which exists because of a lack of knowledge. The first 
demands more light; the latter dreads light. 

From what I have seen in Wisconsin, I am convinced 
that the most powerful aid to that action against the disease 
which this Commission is so anxious to bring about, is public 
demonstration. One animal slaughtered before a body of 
farmers, and the diseased parts exposed to their plain view, 



120 BOVINE TUBERCULOSIS 

is worth more to foster conviction and inspire effort than any- 
thing else that can be done. If the federal and state govern- 
ments would devote means for this demonstration work, it 
would prove a most powerful educator. Public agitation, 
in farmers' gatherings, and the talk of the Agricultural Press 
is useful mainly, in keeping alive an interest in the subject. 
But gentlemen, we must remember that with the majority 
of men, a large majority, — "Seeing is believing". 

I believe therefore, that this Commission should use its 
influence in urging legislation by municipalities, and state and 
national legislatures for the spread and support of this demon- 
stration work. Great care must be exercised, however, to 
select only such animals as will amply show forth the ravages 
of the disease. The great progress we have made in legisla- 
tion in Wisconsin, and in securing wide spread acquiescence 
in the use of the tuberculin test, would never have come had it 
not been for a large number of public demonstrations held 
in various parts of the state. 

We have gone as far as this in legislation: After December 
1, 1910, all animals sold for breeding or milking purposes, 
must first be tuberculin tested. This, I believe, is a step 
further in advance than has been taken by any other state. 
It shows well the tone and temper of our farmers and the 
work which has been done to acquaint them with a true under- 
standing of the situation. It is needless for me to say that 
if they are for the law, or any law, it goes; if they are against 
it, it is at best a dead letter. It is worth a great deal in the 
promotion of such objects, to have a live stock sanitary board 
in a state that will take a hold and lead in this work. In too 
many instances these organizations are purely negative, in 
their influence, and so nothing is done. There is a notable 
lack of funds to bear the expense of demonstration work. The 
farmers everywhere would willingly be taxed for its support. 
Municipalities could well afford to have such expense for the 
sake of the education it would afford to consumers of m^at 
and dairy products. 



APPENDIX 121 

In conclusion, I would urge upon this Commission that 
special emphasis be placed upon the promotion of public 
exhibitions of diseased cattle before and after slaughter, as 
the most powerful means of education concerning the nature 
and danger of bovine tuberculosis. 

(Signed) W. D. Hoard. 



REPORT OF COMMITTEE ON LOCATION OF TUBERCULOSIS IN 

CATTLE 

Your committee on the location of tuberculosis in cattle 
desires to submit the following as its report upon this subject. 
Though we are all agreed that no method for detecting tuber- 
culosis in cattle equals the tuberculin test, we are forced to 
recognize that the universal application of the test under 
existing conditions is practically and economically impossible. 
The number of cattle to be tested, for example, is so great 
that, if all the available veterinarians and all such other per- 
sons as may be trusted to make tuberculin tests should be 
started on this work at once, and kept at it, years would 
pass before all the cattle in the United States and Canada 
could be tested even a single time. Consequently, our efforts 
to locate tuberculosis among cattle should depend primarily 
upon other means than the tuberculin test. 

The tuberculin test should be regarded as having only an 
incidental value in the systematic work of locating tubercu- 
losis, and as being of preeminent importance when we under- 
take the determination of the extent to which the disease is 
prevalent at any point in any herd where it has been located 
by other means or, incidentally by the tuberculin test. 

In the order of seeming importance the means of location 
may be placed as follows: 

I. NOTIFICATION 

A law should be enacted requiring any and every person 
having knowledge of the existence of a case of tuberculosis 



122 BOVINE TUBERCULOSIS 

among cattle to report the same without delay to some proper 
designated authority. Such a law would be practically equiv- 
alent to the obligatory reporting of all clinical cases of tuber- 
culosis which must be recognized as the most serious dissem- 
inators of tubercle bacilli and propagators of tuberculosis. 

Since all cases of tuberculosis that are centers from which 
infection is being scattered, gradually become clinically recog- 
nizable, obligatory notification of all recognized cases of tuber- 
culosis would alone in the course of a few years locate the 
majority if not all badly diseased herds. It would certainly 
locate tuberculous cattle and herds faster than they can be 
handled for some years to come. 

II. EVIDENCE THROUGH MEAT INSPECTION 

An effort should be made to trace tuberculous animals 
back from slaughter-houses to the farms from which they 
were derived. This is important because if the well-condi- 
tioned animals which go to slaughter for meat are tuberculous 
it is probable that among the animals retained on the farm 
some active disseminators of tubercle bacilli exist, which are 
retained at the farm either through ignorance or a false idea 
of economy. 

Meat inspection has already done much to establish infected 
areas from which tuberculous animals have been sent to market. 
At present, however, it is difficult to trace animals to farms 
from which they were shipped, and some method of identifi- 
cation by means of which any animal found on the killing 
floor to be tuberculous can be traced to its place of origin is 
greatly to be desired. A federal law requiring appropriate 
tagging, branding or otherwise identifying all hogs and dairy 
cattle moving interstate for slaughter, and state laws com- 
pelling similar identity marks for these animals moving within 
the state for slaughter, would be the means of locating a 
large proportion of the centers of tuberculosis. Experimental 
work of this character which has been carried out in the past 
has given very interesting results. For instance, when the 



APPENDIX 123 

occurrence of tuberculosis among hogs at an abattoir is fol- 
lowed up by a tuberculin test of the cattle on the home farm 
it practically always discloses tuberculosis among these ani- 
mals. Like much other evidence this encourages us to believe 
that tuberculosis among hogs will cease to exist as an econom- 
ically important problem as soon as we succeed in controlling 
the bovine source of tubercle bacilli. 

III. THE TUBERCULIN TEST 

When the tuberculin test is applied to cattle for any pur- 
pose it should be clearly understood that the reacting animals 
are to be regarded in every sense of the word as recognized 
cases of tuberculosis, which under an obligatory notification 
law, must be reported at once to the proper authority. In 
this way tuberculin will serve as an important means of locat- 
ing tuberculosis among cattle that are tested for reasons like 
the following: 

(1) To obtain healthy animals for export. 

(2) To make sure that animals imported are free from 
tuberculosis. 

(3) To make sure that animals intended for interstate 
movement are free from tuberculosis. And here we would 
like to suggest that the states should protect themselves as 
much as possible against bovine tuberculosis by insisting that 
no new cattle shall be brought in until they have been shown 
by the tuberculin test to be free from tuberculosis. The 
time we may hope is not far off when even breeders of excep- 
tionally fine strains of blood will begin to realize that the 
very best blood coupled with tuberculous infection is an article 
to be shunned, not because we wish to imply that tuberculosis 
is hereditary, but because we know how readily it is con- 
veyed from animal to animal by contact. 

(4) To obtain milk from animals shown in the most 
conclusive manner to be free from tuberculosis, irrespective 
of whether the milk is intended for special certification or for 
more general or regular city use. 



124 BOVINE TUBERCULOSIS 

(5) To satisfy an owner of cattle that his herd is free 
from tuberculosis or to give him the information he needs to 
clean his herd from disease. 

In whatever way the tuberculin test is applied, or for what- 
ever purpose, all positive reactions obtained should be regarded 
as placing the reacting animal in the category of recognized 
cases of tuberculosis, which must be reported under a notifi- 
cation law. 

As the newer methods of applying tuberculin for test pur- 
poses have not been found to be as reliable as the older, sub- 
cutaneous method, they cannot be advocated. The ophthalmo 
and cutaneous tuberculin tests may have a value in some 
special cases, as for example, where doubt exists about the 
reliability of a subcutaneous test because an animal may have 
been subjected to some pernicious manipulation. In this sense 
these latter modes of applying tuberculin should be kept in 
mind. 

IV. EXAMINATION OF MATERIAL FROM CATTLE AND HERDS 

The valuable evidence that may be obtained as to the loca- 
tion of tuberculosis through the examination of milk, cream, 
butter, centrifuge slime and other products and materials from 
cattle should not be neglected, especially when these examina- 
tions are made by health officers and others for the protection 
of public health, and are followed up by the inspection of the 
animals and the character of their environment as a routine 
procedure. Such inspections are constantly becoming more 
prevalent in various sections of the United States and Canada. 

V. MOST IMPORTANT SOURCES OF ANIMAL TUBERCULOSIS 

Tuberculosis as it exists among the domestic animals of 
America, today, undoubtedly owes its primary introduction 
to the cattle of improved breeding that have been imported 
from European lands from time to time in the past, for the 
purpose of improving the native stock of the country. No 
particular breed is to be incriminated in this charge, as several 



APPENDIX 125 

of the most prominent and popular breeds have been found 
guilty of furnishing tuberculous individuals to the best Amer- 
ican herds on repeated occasions. The knowledge that infec- 
tion has taken place from these sources in the past affords us 
a valuable indicator of the points where search should be made 
in our efforts to detect the cases of tuberculosis that exist today 
upon the farms of the country. First of all then, attention 
may be directed toward all herds of pure bred cattle whether 
of beef or dairy type, especially to those from which cattle 
are sold, either by private or public sale, and from which cattle 
are thus distributed to various parts of the country; also to 
herds from which members are exhibited at fairs and exhibi- 
tions; and herds which keep males for custom service. 

In addition to these herds of pure bred cattle there are 
many others to which well bred stock has been added for the 
purpose of grading up and improving the quality of the indi- 
viduals of the herd. 

These in some instances have received the infection of 
tuberculosis with the new animals from which such great 
benefits had been expected, and these herds of well graded 
cattle should also be regarded with suspicion until they have 
been proved to be free of tuberculosis. Next in order should 
come all dairy cattle, but the methods by which the disease 
may be located in these herds have been discussed above. 
(Signed) John R. Mohler, Chairman. 
J. W. Flavelle. 

C. A. HODGETTS. 

REPORT OF COMMITTEE ON DISSEMINATION OF BOVINE TUBER- 
CULOSIS 

The subcommittee on the dissemination of bovine tuber- 
culosis respectively submits the appended report on the means 
for the dissemination of this disease, based on the present 
knowledge of the life history of the tubercle bacillus. The 
possible means for the dissemination of this disease are enumer- 
ated as follows: 



126 BOVINE TUBERCULOSIS 

1. The introduction into a sound herd of an animal or 
animals affected with tuberculosis (a) those with open tuber- 
culosis (b) those in which the disease is in the period of incuba- 
tion and (c) those in which the lesions are temporarily arrested. 

The last group will not transmit the infection speedily and 
possibly may never do so. The first group is certain to spread 
the virus. 

2. By feeding calves milk, whole or separated, butter- 
milk or whey, where the milk has come from tuberculous cows. 

3. By bringing cattle suffering from open tuberculosis in 
contact with healthy ones at fairs, cattle shows and other 
exhibitions. 

4. By shipping healthy cattle in cars not thoroughly 
disinfected, recently occupied by tuberculous cattle. 

5. By placing healthy cattle in stables that have not 
been thoroughly disinfected and which were recently occu- 
pied by tuberculous animals, as frequently happens with the 
change of farm ownership or tenants. 

6. Tuberculous animals which do not react to tuberculin 
such as those in the period of incubation or latent cases, but 
which develop active tuberculosis later, are frequently car- 
riers of the virus although bought and sold as sound animals. 
These can not at present be differentiated from sound animals. 
Therefore all cattle coming from herds in which the disease 
exists should be considered as suspicious. The sound herd 
is the unit to deal with. 

7. Tubercle bacilli may be transmitted by tuberculous 
cattle running in a pasture to healthy cattle in adjoining pas- 
tures where they are separated by a fence of such nature that 
the cattle may get their noses together. 

8. Tuberculosis in cattle rarely, if ever, occurs through 
infection from (a) man, either directly or as a carrier of bovine 
tubercle bacilli, (b) from other species of animals, or (c) by 
infection from the droppings of crows, buzzards or other birds or 
carnivorous animals that have fed upon the carcasses of tuber- 
culous cattle. It is the opinion of this committee that bovine 



APPENDIX 127 

tuberculosis is spread largely through the introduction of 
tuberculous cattle into sound herds; by the feeding of calves 
with infected milk, or milk products; by exposing sound 
animals to infected ones at fairs, or other cattle shows; and 
by exposing them to infected cars and stables. There are 
other ways in which now and then it is possible that an animal 
may become infected but the means of dissemination men- 
tioned in this paragraph are those to be guarded against in 
formulating efficient methods of control. 

(Signed) V. A. Moore, Chairman. 

E. C. SCHROEDER. 

M. P. Ravenel. 

REPORT OF COMMITTEE ON DISPOSITION OF TUBERCULOUS 

ANIMALS 

Your committee on the Disposition of Tuberculous Animals 
begs to submit the following report: 

In the work of control and eradication of tuberculosis in 
animals it is first of all of the utmost importance to establish 
the presence of the disease in all the affected cattle, since 
only by such a procedure will it be possible to guard the 
healthy and newly born animals from infection. 

Fortunately we are in a position to determine with con- 
siderable certainty the vast majority of occult cases of tuber- 
culosis in cattle, even the incipient cases, with the aid of tuber- 
culin, and the clinical cases by physical examination. This 
alone constitutes a great advantage in the work of suppression 
of the disease. The tuberculin test should therefore be con- 
sidered as a very important step in the eradication of tuber- 
culosis. As a matter of fact all the recognized authorities 
on the subject are agreed on this point. Once the tuberculous 
animals are recognized consideration must be given to the 
most suitable and economical way of eradicating the disease 
from the herd. This naturally brings up the question of the 
disposition of the tuberculous animals, and in adopting any 
particular method one should be guided by the extent of the 



128 BOVINE TUBERCULOSIS 

infection of the herd, the quality of the affected animals, the 
sanitary condition of the premises, and last but not least, the 
owner's intelligence and knowledge of the subject. The latter 
information is necessary to determine if reliance can be placed 
on the owner to carry out minutely all the details which are 
essential in executing any particular method of eradication 
that may be decided upon. The owner's cooperation in this 
work is without doubt a very essential feature of this great 
task. For this reason a campaign of education of the farmers 
and stock raisers relative to the control of tuberculosis in 
which all the advantages of the eradication of tuberculosis 
must be impressed on them, would greatly facilitate this im- 
portant campaign. It is a well known fact that any voluntary 
method of suppression by the herd owners themselves would 
bring about better and quicker results than when compulsory 
measures are enforced upon them by legislative enactments. 
Nevertheless the time has arrived when a campaign looking 
towards the control of this disease should be entered upon by 
the general government as well as the state and province. 
This campaign must reach in the first place all the clinical 
pulmonary forms of tuberculosis; then tuberculosis of the 
udder, intestines and uterus. 

Having removed these exceedingly dangerous cases the 
balance of the tuberculous herd may be treated by the Bang 
system, which consists of the establishment of two herds of 
cattle, one containing the animals which react to tuberculin, 
and the other those that prove to be healthy. Each class of 
cattle is kept entirely separate from the other, in different 
stables when possible, and under the care of separate attend- 
ants, using separate utensils. The calves born of the diseased 
cows are removed from their mothers at birth and placed in 
the stable with the healthy animals where they are reared 
upon the milk of healthy cows or upon other milk which has 
been properly pasteurized. In this way the healthy portion 
of the herd constantly increases while the diseased animals 
are disposed of as rapidly as may be deemed necessary until 



APPENDIX 129 

finally all of them are gone and the remaining herd is com- 
posed entirely of healthy cattle. The tuberculin test is applied 
to the healthy herds at regular intervals, annually or semi- 
annually, in order to detect any cases of latent tuberculosis 
or recent infection which may appear. 

A modification of the Bang system is Ostertag's method 
of suppressing tuberculosis. This system demands only a 
clinical examination of the original herd with the elimination 
of all open cases of tuberculosis. The calves from the remain- 
ing cows are immediately removed and brought up on pas- 
teurized milk in the same manner as in the Bang system and 
a new herd is thus established from the young stock. Healthy 
nurse cows could be used for these calves instead of feeding 
them on pasteurized milk. The tuberculin test is applied to 
this new herd at stated intervals in order that any cases of 
tuberculosis which may develop therein may be discovered 
promptly. Neither of these systems, however, has met with 
much favor in this country as it required a considerable length 
of time and care to create a herd free from tuberculosis by 
either of them. Nevertheless the inauguration of Bang's or 
Ostertag's method in herds of valuable animals whether they 
be dairy or beef breeds is unquestionably of an economic value 
and in such cases either of these systems should be encouraged. 
On the other hand, in ordinary beef or dairy herds the practice 
of Bang's or Ostertag's method in this country has not met with 
much encouragement, owing to the extraordinary supervision, 
time and labor, as well as the loss of market milk from the 
reacting cows which it involves. 

In such herds the best ultimate results have thus far been 
obtained by the obligatory disposal of all the clinically affected 
cows and giving the dairyman the alternative either to pasteur- 
ize the milk from the remainder of his herd, or to be forced to 
refrain from selling the raw milk from the infected herd at all. 
In case he adopts the former method the herd composed of 
diseased and healthy cattle should be placed in quarantine 
under the supervision of sanitary authorities, and no sales 



130 BOVINE TUBERCULOSIS 

should be permitted from the herd excepting for immediate 
slaughter. The alternative method will compel him to dispose 
of his tuberculous animals in the case he refuses to pasteurize 
the milk. The suppression of tuberculosis could be greatly 
facilitated and the cooperation of many of the herd owners 
could be gained by a provision by which a certain percentage 
of indemnity could at least for a term of years be paid for the 
condemned animals. The scale for such an indemnity should 
be arranged in accordance with the final disposition of the 
carcass under competent inspection. 

Another method of eradication should receive serious con- 
sideration as being of value in some localities. This is known 
as the Manchester system, which is either the Ostertag or 
Bang system applied to localized areas or even individual 
farms, from which centers the work progresses to surrounding 
or neighboring districts and farms. 

Inasmuch as the animals affected with clinical tuberculosis 
are the greatest sources of danger in the dissemination of the 
disease, compulsory reporting of such cases should be inaug- 
urated by the state, as is now done in many places in the con- 
trol of human tuberculosis. Mandatory reporting of these 
cases and their prompt slaughter are very essential, as only 
by the elimination of these exceptionally dangerous cases can 
it be hoped to take up all the other details by which a successful 
control of bovine tuberculosis may be accomplished. 

In conclusion your Committee, having regard to the dispo- 
sition of pure bred cattle, or valuable animals kept for either 
breeding or dairy purposes, would strongly recommend a 
system requiring the removal of all clinical tuberculous ani- 
mals from the herd, the segregation of all calves from the 
remaining cows in order to establish a new, clean herd, the use 
of tuberculin tested nurse cows or pasteurized milk for these 
calves, and the periodic application of tuberculin to this newly 
established herd, as the only thoroughly reliable one. 

(Signed) W. C. Edwards, Chairman. 
John R. Mohler. 
Frederick Torrance. 



APPENDIX 131 

THE commission's RECOMMENDATIONS ON ERADICATION — A 
COMPOSITE OF THE METHODS OF BANG AND OTHERS. 

The Commission after stating the known facts regarding 
the nature of tuberculosis and enumerating the principles to 
be observed in its prevention and eradication, recommends 
the following plan of procedure: It is recognized that in several 
points there are opportunities, in order to meet individual needs, 
to change or modify the directions herein given. It is under- 
stood, however, that whenever such modifications are made 
they should conform in the greatest detail to the principles laid 
down in the report of this Commission. The plan has for its 
purpose the conservation of the herd whenever that is possible. 

The control of bovine tuberculosis involves a definite pro- 
cedure under two distinct and different conditions, namely: 
(1) where a herd of cattle is free from tuberculosis and it is to 
be kept so, and (2) where one or more animals in the herd are 
infected and the purpose is to eradicate the disease and estab- 
lish a sound herd. 

PROCEDURE UNDER CONDITION ONE 

The prevention of tubercular infection in cattle, free from 
tuberculosis, consists simply in keeping tuberculous cattle or 
other animals away from the sound ones; in keeping tuber- 
culous animals out of pastures, sheds or stables where the sound 
ones may be kept. Healthy cattle should not be exposed to 
possible infection at public sales or exhibitions. Raw milk or 
milk by-products from tuberculous cows should not be fed to 
calves, pigs, or other animals. Cars that have not been thor- 
oughly disinfected should not be used for the transportation 
of sound cattle. Cattle that are purchased to go into sound 
herds should be bought from healthy or sound herds only. 

PROCEDURE UNDER CONDITION TWO 

The eradication of tuberculosis from infected herds requires 
for conservation of the herd different procedures according to 



132 BOVINE TUBERCULOSIS 

the extent of the infection. For a guide to the control of the 
disease, tuberculous herds may be divided into three groups, 
namely: 

I. Where fifty per cent or more of the animals are infected. 

II. Where a small percentage (15% or less) of the animals 
are affected. 

III. Where a larger number (15% to 50%) of the animals 
are diseased. 

In eliminating tuberculosis from infected herds the follow- 
ing procedure is recommended: 

GROUP I 

Herds where a tuberculin test shows fifty per cent or more 
of the animals to be infected should be treated as entirely 
tuberculous. The procedure here is as follows: 

1. Eliminate by slaughter all animals giving evidence of 
the disease on physical examination. 

2. Build up an entirely new herd from the off-spring. The 
calves should be separated from their dams immediately after 
birth and raised on pasteurized milk or on that of healthy nurse 
cows. This new herd must be kept separate from any reacting 
animals. 

3. The young animals should be tested with tuberculin at 
about six months old, and when reactors are found at the first 
or any subsequent test— the others should be retested not more 
than six months later. When there are no more reactors at 
the six months' test annual tests should thereafter be made. 
All reacting animals should at once be separated from the new 
herd and the stables which have been occupied thoroughly 
disinfected. 

4. When the newly developed sound herd has become of 
sufficient size the tuberculous herd can be eliminated by 
slaughter under inspection for beef. 

GROUP II 

1, The reacting animals should be separated from the non- 



APPENDIX 133 

reacting ones and kept constantly apart from them at pasture 
in yard and in stable. 

(a) Pasture. The reactors should be kept in a separate 
pasture. This pasture should be some distance from the other 
or so fenced that it will be impossible for the infected and non- 
infected animals to get their heads together. 

(b) Water. When possible to provide otherwise reacting 
cattle should not be watered at running streams which after- 
wards flow directly through fields occupied by sound cattle. 
The water from drinking troughs used by infected animal sshould 
not be allowed to flow into stables, fields or yards occupied by 
sound animals. 

(c) Stable. Reacting cattle should be kept in barns or 
stables entirely separate from the ones occupied by the sound 
animals. 

2. Calves of the reacting cows should be removed from 
their dams immediately after birth. Milk fed these calves 
must be from healthy cows, otherwise, it must be properly 
pasteurized. These calves should not come in contact in any 
way with the reacting animals. 

3. The non-reacting animals should be tested with tuber- 
culin in six months, and when reactors are found at the first six 
months, or any subsequent test, the others should be retested 
not more than six months later. When there are no more re- 
actors at the six months' test, annual tests should thereafter be 
made. All reacting animals should at once be separated from 
the new herd and the stables which they have occupied thor- 
oughly disinfected. 

4. The milk of the reacting animals may be pasteurized 
and used. 

5. Any reacting animal which develops physical symptoms 
of tuberculosis should be promptly slaughtered. 

6. An animal that has once reacted to tuberculin should 
under no circumstances be placed in the sound herd. 

7. As soon as the sound herd has become well established, 
infected animals should be slaughtered, under proper inspection. 



134 BOVINE TUBERCULOSIS 

GROUP III 

Herds that come within this group should be dealt with 
either as in Group II, where the herd is separated, or as in 
Group I, where all of the animals are considered as suspicious 
and an entirely new herd developed from the offspring. 

GENERAL PRECAUTIONS 

In ALL cases animals that show physical evidence of the 
disease should be promptly eliminated. They should be de- 
stroyed if the disease is evidently far advanced, if not, they may 
be slaughtered for food under proper inspection. 

All milk from tuberculous cows that is used for food pur- 
poses should be thoroughly pasteurized. This means that it 
must be heated sufficiently to kill or to render harmless, any 
tubercle bacteria that may be present in it. For this, it is 
necessary to heat the milk for twenty minutes at 149° F. or for 
five minutes at 176° F. It is important that pails or other 
utensils used in carrying the unpasteurized milk should not be 
be used, unless previously sterilized, for storing the milk after 
it is pasteurized. 

When diseased animals are found, the stables from which 
they are taken should be thoroughly cleansed and disinfected. 
To accomplish this, all litter should be removed; floors, walls 
and ceilings carefully swept and the floors together with man- 
gers and gutters, thoroughly scrubbed with soap and water. 
Thorough cleaning before the application of the disinfectant, 
cannot be too strongly emphasized. After cleansing, the dis- 
infectant should be applied. A five per cent (5%) solution of 
carbolic acid, a 1-1,000 solution of corrosive sublimate or a four 
per cent (4%) solution of sulphuric acid may be used. 

When the stable can be tightly closed, formaldehyde gas 
properly used is reliable and satisfactory. 

If tuberculous cattle have been kept in a small yard the 
litter should be removed, the surface plowed and the fencing 
and other fixtures thoroughly cleansed and disinfected. 



ILLUSTRATIONS 



PLATE I. 

Tubercle bacteria. Photographs of tubercle bacteria. 1. Bovine variety, 
from a young culture on glycerin agar. 2. Bovine variety from the mouth of 
a cow having advanced pulmonary tuberculosis. 3. Avian tubercle bacteria 
from a glycerin agar culture. (X about 1000.) 




*#■" 






1 




4-n-- ^ 



:^' 



^ 



A 





} ^v . 



IM.ATE I TUBERCLE BACTERIA 



PLATE II. 

Cultures of tubercle bacteria. 1. Growth of bovine variety of Bacterimn 
tuberculosis on glycerin agar. 2. Growth of same organism on egg medium. 

(Natural size.) 



1 2 

PLATE II. CULTURES OF TUBERCLE BACTERIA (Bovine variety) 



PLATE III. 

Growth of tubercle bacteria on glycerin bouillon. A photograph of the 
surface growth of bovine tubercle bacteria on glycerin bouillon. It shows 
the pushing up of the growth along the sides of the flask at the margin. The 
wrinkled surface of the growth is slightly in evidence. 







PLATE III. CULTURE OE TUBERCLE BACTERL^ ON (iLVCERIN liOUILLON 

(Natural size) 



PLATE IV. 

Structure of tubercle. 1. A drawing of a section of very young tubercles 
in the spleen (After Thoma). The tubercle at the left shows simply epithe- 
lioid cells, the one at the right shows the necrotic center with giant cells con- 
taining tubercle bacteria and the zone of epithelioid cells surrounded by a 
zone of small round cells (lymphocytes). 2. A photograph of a section of 
a chicken's liver showing several small tubercles. The necrotic center and 
surrounding zone of epithelioid and giant cells and the one of round cell in- 
filtration surrounding it. (X about 10.) 






I'LATE IV. STKUCTUKK OF YOUNG TUBERCLES 



PLATE V. 

Temperature curves. After tuberculin. 1. Shows the temperature 
curves in unquestioned tuberculin reactions. 2. Shows the temperature 
curves when the elevation is slight and there is doubt whether they are 
reactions or not. 3. The normal temperature. 



TEMP BEFOR^E HOURS AFTER INJECTION 

4 2 8 12 16 20 


o 
106 

105 

104 

I03 

102 

10! 

100 

99 
































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106° 
I05 
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PLATE V. temperati'kf: curves. 



• PLATE VI. 

Bronchial glands. Trachea and bronchial tubes of bovine lungs showing 
attached bronchial glands, (a-a') Supply right and left caudal lobes, (b-bM 
supply r. and 1. ventral lobes, (c-cV) branches of the right supernumerary 
bronchus, (c-) supply left cephalic lobe, (d) branch of azygous lobe, (e) 
trachea. A. Left bronchial lymph gland. B. Right bronchial lymph 
gland. C. Lymph gland base of supernumerary bronchus. D. Gland 
often between bronchi. The glands A. to D. are often involved (Smith) 




PLATE VI. BRONCHIAL GLANDS (.Smith) 



PLATE VII. 

Tiiberatlous lung. This is a photograph of a section of the anterior lobe 
of a cow's lung advanced in tuberculosis. The entire lung tissue is involved. 
The tuberculous masses are surrounded in some instances by a quite thick 
band of connective tissue. A large part of the tissue is calcified. This is 
shown by the Ught or whitish points. (Natural size.) 




PLATE VII TUBERCULOUS LUNG 



PLATE VIII. 

Tubercle opening into bronchus. This shows a section through a bronchus 
where at point (a) the tuberculous tissue has extended into the bronchus 
making it possible for the tubercle bacteria from the tuberculous area to 
pass into the bronchus and through it to the mouth. From the mouth they 
are disseminated with the droolings or they are swallowed and appear in the 
intestinal contents. (Natural size.) 




PLATE VIII. TUBERCLE DISCHARGINC, INTO BRONCHUS 



PLATE IX. 

T?<berciilous king, diaphragm and liver. This photograph shows a piece 
of the lung (a) attached to the diaphragm (b) by a mass of tuberculous tissue 
growing out from the serous membrane. The liver (c) is lying just beneath 
the diaphragm. The anterior surface of the diaphragm is covered with 
tuberculous nodules (d) which have fixed the margin of the lung to it. 
(Natural size.) 




PLATE IX TUBERCULOUS DIAFHRAC;M 



PLATE X. 

Tuberculous nodules on lung. This is a photograph of a few large tubercu- 
lous nodules on the margin and surface of a cow's lung. The normal lung is 
shown at (aj. The tuberculous masses which were calcified are shown at 
(b). (Natural size.) 




~a 




'•<"^*^. 






PLATE X. TUBERCULOUS GROWTH ON LUNG 



PLATE XI. 

Titberciiloiis pleura. This is a photograph of the tuberculous prominences 
or nodules that have developed on the pleura covering the ribs. (Natural 
size.) 




PLATE XI. TIBERCI KS ON PLEURA OVER RIBS 



PLATE XII. 

A cross section of a cow's heart. This is a photograph of a cross section 
of a tuberculous heart. It shows a thick tuberculous deposit surrounding the 
heart muscle, (a) Heart muscle of the right and left ventricles, (b) a layer of 
fat between the heart muscle and the tuberculous deposit (c) beneath the peri- 
cardium. This tuberculous deposit much of which is calcified surrounds 
the entire heart extending with about equal thickness from the apex to 
the base. (Slightly reduced in size.) 




PLATE XII. SECTION OF A TUliERCULOUS HEART (Cowl 



PLATE XIII. 

Tuberculous gland. A photograph of a cross section of a much enlarged 
lymph gland. The lighter points indicate centers of calcification. The cen- 
tral area shows infiltrated tissues and the breaking down of the gland tissue. 
(Natural size.) 



xj-^- 



PLATE XIII. TUBERCULOUS GLAND 



PLATE XIV. 

Mediastinal gland. A photograph of a much enlarged tuberculous medias- 
tinal glapd cut longitudinally. The central portion shows necrosis and break- 
ing down of the tissue. This gland is normally not more than one and one- 
half inches long. (Natural size.) 




PLATE XIV. TLBERCULOUS GLANU 



PLATE XV. 

Tuberculous gland. A photograph of ( 1 ) a mediastinal gland showing small 
tubercles (a) many of which are caseous. (2) A chain of lymph glands that 
are much enlarged. The lower one is split and spread open showing the 
broken down tissue. (Natural size.) 



^^ci^'- 




/ 



r 



\ 






a 






PLATE W. TUBERCULOUS GLANDS 



PLATE XVI. 

Mediastinal gland. A photograph of a longitudinal section of a very 
large mediastinal tuberculous gland. The outer part shows broken down 
tissue. The central portion contains a mass of homogeneous exudate occasion- 
ally found in the interior of tuberculous glands. (Reduced about one-half.) 




PLATE XVI. TUBERCULOUS MEDLXSTINAL GLANU 



PLATE XVII. 

Enlarged mesenteric glands. This photograph shows a chain of very much 
enlarged tuberculous glands (a). They are several times larger than normal. 
They are hard and contain areas of calcified tissue. (Slightly smaller than 
natural specimens.) 




PLATK XVII. ENLARGED ( tuberculous i MESENTERIC GLANDS 



PLATE XVIII. 

Ulcers in the intestine. This is a photograph of two short strips of the 
small intestine of a cow showing several small and two large tuberculous 
ulcers. (Natural size.; 





PLATE Will TUHERCULOl S ULCERS INTESTINE 



PLATE XIX 

Ulcers and enlarged glands at ileo-caecal valve. A photograph of several 
small ulcers in the small intestine (a) and a few in the large intestine (b). 
The lymph glands (c) at the ileo-caecal valve are much enlarged from tuber- 
culous growth. (Natural size.) 




PLATE XIX. TUBERCULOUS ULCERS AND GLANDS AT ILEO CAECAL VALVE 



PLATE XX. 

Liver. A photograph of the surface of a small part of the liver of a cow 
sprinkled with tubercles. The tubercles do not extend deep into the tissue 
but are confined to the surface. (Natural size.) 




I'LATE X\. TUBERCLES ON SURFACE t)K LIVER 



PLATE XXI. 

Cross section of liver. A photograph of a cross section through the portal 
gland of a tuberculous liver of a cow. It shows several tuberculous masses 
(a) within the liver tissue. In some of these the dead tissue is beginning 
to calcify. The portal gland (b) is very much enlarged and tuberculous 
throughout. (Reduced in size.) 




PLATE XXI. A SECTION OE A TUBERCULOUS LI\EK 



PLATE XXII. 

Omenliim. A photograph of a part of the omentum showing a large number 
of small more or less flattened tubercles scattered over the surface. (Slightly 
reduced in size.) 




PLATE XXII. A TUBERCULOUS OMENTUM 



PLATE XXIII. 

Omentum. This is a photograph of a part of an omentum (cow) covered 
with confluent tubercles. It is a much older and more advanced case than 
the one shown in Plate XXII. The entire surface is covered. (Natural size.) 




PLATE XXIII. A TUBERCULOUS OMENTUM 



PLATE XXIV. 

Omentum. This photograph shows an omentum (cow) thickly studded 
with spherical tubercles some sessile and others attached to the omentum by 
a slender thread of tissue. When sectioned they exhibit dead and partly 
calcified tissue in the central part. (Natural size.) 




PLATE XXIV. A TUBERCULOUS OMENTUM 



PLATE XXV. 

Spleen. A photograph of the spleen of a cow showing tubercles within 
the spleen pulp. Several of them contain points of calcification as indicated by 
the whitish points in the dead tissue. (Considerably reduced in size. ) 




PLATE. XXV. TUBERCULOUS SPLEEN (Cow) 



PLATE XXVI. 

Udder. A photograph of a section through a tuberculous udder of a cow. 
Milk from this udder contained an enormous number of tubercle bacteria. 
In the living animal the evidence of disease was the slightly swollen and 
very hard condition of the gland. (Slightly reduced in size.) 




PLATE XXVI A TUIiERCULOUS UDDER 



PLATE XXVII. 

Skin. A photograph of several sections of the skin each showing a cross 
section of a tubercle (b) lying in and immediately under the derma. This 
is a somewhat rare location for tubercles. (Natural size.) 




PLATE XXVIl. TUBERCULOSIS OE THE SKIN 



PLATE XXVIII. 

Uterus. A photograph of a tuberculous uterus of a cow. The entire 
interior surface of the uterus is studded with tubercles. It shows the interior 
from the os to the fundus. (One-half natural size. ) 




PLATE XXVIII TUBEKCUI.OSIS OF THE UTERUS 



PLATE XXIX. 

Bone. This is a photograph of a longitudinal section through the spinal 
cord and vertebrae. It shows a large tuberculous mass partially calcified 
in the vertebra with some pressure upon the spinal cord. This specimen 
was given me by Dr. W. L. Beebe of St. Paul, Minn. (Natural size.) 




PLATE XXIX TUBERCULOSIS OF BONE 



PLATE XXX. 

Spleen. This is a photograph of a pig's spleen containing several tuber- 
cles. This pig was infected by drinking the milk from a cow having tuber- 
culosis of the udder. (Natural size.) 




PLATE XXX. TUMEKCI.es IN A I'ICS SPLEEN 



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APR 15 l^^3 



